roes 


SKETCHING  METHODS 


BY 


W.  C.  SWEENEY 

Captain  21st  U.  S.   Infantry 


The  Hicks-Judd  Company 
San  Francisco,  Cal. 


Copyright, 
By  CAPT.  W.  C.  SWEENEY, 
SAN  FRANCISCO. 


CONTENTS. 

PAGE 

Object  of  sketching 9 

Classification  of  sketches  .         .         .        .  18 

Outline  for  beginner          .         .         .  19 

Sketching  tools 24 

To  orient  the  board 24 

Conventional  signs    .....  34 

Title 43 

Scales 45 

What  a  sketch  should  show     ...  56 

Horizontal  detail 57 

Traversing      .        .        .        .        .        .  58 

Intersection     .        .        .        .        .        .58 

Resection 59 

Estimation .60 

Vertical  detail 61 

Contours         .        .        .        .        .        .64 

Detail  shown  by  contours     ...  66 

Logical  contouring 69 

Contour  framework       .        .        .        .  71 

Notes  for  field  work        ....  78 

Position  sketch 81 

Adjustment  to   close         ....  84 

Completing  sketch     .....  85 

Outpost  sketch  .  87 
Place  sketch       .        .        .        .        .        .89 

Road  sketch 91 

Reconnaissance  sketches    ....  98 

366457 


INTRODUCTION. 

The  writer's  idea  in  publishing  Sketching 
Methods  is  to  simplify  instruction  in  the 
subject  and  to  clear  away  the  mathematics 
and  the  mystery  which  seem  to  cling  to  it. 
The  average  student  becomes  confused  be- 
cause almost  always  he  is  required  to  study 
map  making  before  he  gets  started  on  sketch- 
ing and  the  result  is  a  jumble  of  ideas  until  he 
learns  to  work  without  instruments.  When 
he  learns  this  he  has  learned  to  sketch.  It  is 
thought  that  a  presentation,  in  as  condensed 
form  as  possible,  of  the  methods  developed 
by  expert  sketchers  at  the  Army  Service 
Schools  will  be  of  great  assistance  not  only  to 
students  but  also  to  instructors.  The  writer 
believes  that  there  is  no  necessity  for  teaching 
the  use  of  the  clinometer  and  scale  of  slopes 
in  order  to  teach  students  how  to  contour.  He 
believes  that  sketching  can  be  taught  more 
quickly  and  as  thoroughly  by  direct  methods 
than  by  indirect  ones.  He  has  tested  this  belief 
arid  proved  its  soundness.  In  this  time  of 
emergency  it  is  impossible  to  secure  com- 


6  INTRODUCTION 

passes,  pacetallys,  clinometers,  tripods  and 
other  expensive  frills  that  have  been  a  part  of 
sketching  for  so  long".  Even  if  they  could  be 
procured  there  would  not  be  time  to  teach 
their  use,  for  intensive  training  means  train- 
ing under  pressure  and  that  means  do  away 
with  frills  and  get  down  to  practical  and  direct 
methods  of  instruction. 

The  student  should  be  taught  what  scales 
are,  how  to  make  conventional  signs  and  their 
meaning,  how  to  locate  points  both  horizon- 
tally and  vertically,  how  to  estimate  differ- 
ences of  elevation  of  critical  points  and  how 
to  contour  by  logical  methods  and  finally  what 
is  to  be  shown  on  a  sketch.  He  should  then 
be  given  an  area  to  sketch  in  a  limited  time 
for  a  definite  tactical  purpose.  He  should  be 
given  several  such  tasks  to  do,  being  always 
forced  to  work  under  pressure,  and  he  will 
rapidly  develop  the  ability  to  sketch. 

There  is  no  reason  why  every  officer  and 
non-commissioned  officer  should  not  learn  to 
sketch  and  to  read  sketches  within  a  very 
short  time.  The  instructor  must  thoroughly 
understand  the  subject.  Common  sense  must 


INTRODUCTION  7 

be  his  guide.  His  explanations  must  be  clear 
and'  simple,  for  the  average  man,  especially 
one  with  a  little  service,  is  looking  for  some- 
thing hard  when  you  mention  sketching  to 
him.  A  pencil,  paper,  and  home-made  ruler 
and  board  are  sufficient  tools  for  the  experi- 
enced sketcher  and  should  be  enough  for  the 
beginner. 

W.  C.  SWEENEY. 
Presidio,  San  Francisco, 
May  26,  1917. 


MILITARY  SKETCHING 

OBJECT    OF    SKETCHING. 

Military  sketching  is  an  art.  Its  general 
principles  may  be  learned  from  text  books, 
but  the  mechanical  execution  can  no  more  be 
learned  from  them  than  can  the  art  of  paint- 
ing. The  degree  of  proficiency  attainable  de- 
pends upon  the  intelligence  of  the  sketcher  and 
the  amount  of  time  given  to  its  practice. 

A  map  is  a  projection  to  scale  of  the  topo- 
graphic features  of  the  ground.  It  is  made 
with  exact  instruments,  and  its  accuracy  and 
completeness  are  the  primary  considerations 
in  its  making. 

A  military  sketch  is  a  report  of  the  topo- 
graphic features  of  a  section  of  country  in 
which  certain  conventional  signs  are  used  as 
substitutes  for  words.  Its  accuracy  and  com- 
pleteness are  affected  by  the  "time  available," 
the  "instruments  at  hand/'  and  the  "tactical 
conditions"  under  which  the  sketcher  is  work- 
ing. The  difference  between  a  map  and  a 
sketch  must  always  be  in  mind. 


10  SKETCHING  METHODS 

A  report  by  means  of  a  sketch  contains  in- 
formation which  it  is  practically  impossible 
to  convey  by  written  words.  Every  officer, 
below  field  rank,  is  liable  to  be  called  upon  at 
any  time  to  make  a  report  on  the  country 
under  such  conditions  that  only  a  sketch  will 
answer.  All  officers,  especially  those  of  field 
and  higher  rank,  are  constantly  required  to 
read  maps  and  sketches  and  to  make  tactical 
decisions  and  dispositions  based  upon  them. 
The  ability  to  make  a  sketch  guarantees  the 
ability  to  read  and  understand  both  maps  and 
sketches.  A  sketcher  finds  no  difficulty  in 
reading  a  map.  Ridge  and  valley  lines  are  at 
once  apparent,  and  he  reads  the  map  easily, 
rapidly  and  understandingly.  A  sketch  is 
more  difficult  to  read  than  a  map.  One  who 
is  himself  a  sketcher  has  greater  facility  in 
reading  a  sketch,  because  he  can  grasp  the 
sketcher's  meaning  more  quickly  than  can  one 
who  has  never  sketched. 

In  any  well  regulated  scheme  of  instruction 
for  military  officers,  military  sketching  occu- 
pies an  important  and  distinct  place.  The  ne- 
cessity for  having  junior  officers  skilled  in  this 


SKETCHING  METHODS  11 

art  and  the  advantages  accruing  from  the  abil- 
ity of  field  and  higher  ranking  officers  to  read 
sketches  quickly  are  recognized  everywhere. 
In  the  field,  the  report  by  means  of  a  sketch 
is  the  rule,  not  the  exception. 

An  ordinary  use  of  a  sketch  may  be  illus- 
trated by  the  following  assumed  situation 
(%.  1): 

Our  Division  is  marching  south,  in  hostile 
country,  toward  an  enemy  who  was  this  morn- 
ing reported  to  be  about  twenty  miles  south 
of  us  and  moving  north.  Our  cavalry  screen 
is  four  miles  south  of  Y.  Our  regiment  forms 
the  support  of  the  advance  guard. 

The  Colonel  has  a  map  of  the  country  on 
a  scale  of  one  inch  to  the  mile.  This  map  was 
made  several  years  ago.  It  shows  only  the 
flat  detail,  houses,  towns,  roads,  railroads, 
stream  lines,  trees,  etc.  The  undulations  of 
the  country  are  not  shown. 

At  a  halt  along  the  road,  the  Colonel  calls 
to  you,  and  showing  you  his  map,  says :  "I 
will  arrive  at  Y  at  4.30  p.  m.  today  with  the 
point  of  the  advance  guard.  The  Division  will 
camp  tonight  at  Dover  and  the  Advance 
Guard  (less  our  regiment)  about  l/2  mile 
south  of  Dover.  Our  regiment  will  form  the 


12 


SKETCHING  METHODS 


Scale:  l"=  I  mile 


Fig   I 


SKETCHING  METHODS  13 

outpost  on  a  front  from  X  (*/£  mile  west  of 
Y)  through  Y  to  Z  (1  mile  east  of  Y).  Take 
four  mounted  orderlies  and  reconnoiter  from 
X  to  Z  and  far  enough  to  the  front  for  out- 
post purposes  and  report  to  me  at  Y  on  my 
arrival  there.  I  want  such  a  report  as  will 
enable  me  to  determine  how  best  to  dispose 
the  regiment  for  outpost  duty  without  un- 
necessary delay." 

On  the  Colonel's  map,  you  saw  that  Y  is  a 
crossroad  formed  by  the  road  over  which  the 
Division  is  marching  and  the  straight  X-Z 
road. 

You  arrive  at  Y  at  1.00  p.  m.  You  have 
three  and  one-half  hours  in  which  to  make 
the  reconnaissance.  You  must  at  once  recog- 
nize that  only  by  means  of  a  sketch  can  you 
gather  and  convey  the  necessary  information 
to  the  Colonel. 

At  4.30  p.  m.  you  hand  your  sketch  to  the 
Colonel  at  Y.  Reading  it,  he  quickly  gains 
an  idea  of  the  "lay  of  the  land"  and  is  able 
to  dictate  his  order  so  that  his  troops  may  be 
marched  directly  to  their  several  outpost  posi- 
ticns. 

Sketches  vary  in  the  amount  and  value  of 
the  information  that  they  convey  in  exactly 


14  SKETCHING  METHODS 

the  same  manner  as  do  written  messages  and 
reports.    The  same  faults  are  found  in  all. 

It  must  always  be  remembered  that  if  there 
is  plenty  of  time  and  conditions  permit,  the 
commander  will  send  his  engineers  or  others 
with  accurate  instruments  to  make  a  map  of 
the  desired  area.  As  a  consequence,  sketches 
are  made  only  when  there  is  not  time  to  make 
a  map  or  when  conditions  do  not  permit  it. 
The  time  required  to  make  a  sketch  is  always 
a  most  important  factor.  It  will  usually  be 
found  that  the  sketch  is  wanted  for  use  just 
as  soon  as  it  can  be  gotten,  and  often  that 
it  is  wanted  in  such  a  short  time  that  only  an 
outline  of  the  desired  area  can  be  made.  It 
is  in  such  a  case  that  the  judgment,  experi- 
ence, and  tactical  training  of  the  sketcher  play 
such  an  important  part.  If  the  sketch  must  be 
slighted  in  some  parts,  he  must  be  able  to  de- 
termine what  parts  to  slight  and  wrhere  accu- 
racy and  detail  are  necessary,  and  he  cannot 
determine  this  unless,  knowing  the  object  for 
which  the  sketch  is  made,  he  realizes  what  the 
commander  needs  to  know  about  the  ground. 


SKETCHING  METHODS  15 

From  the  foregoing  considerations,  certain 
conclusions  have  been  deduced  for  the  guid- 
ance of  the  sketchier.  These  may  be  summar- 
ized as  follows : 

1.  The  assigned  area  or  distance  should  be 
covered  in  the  time  allotted. 

2.  Clearness  is  very  important.     No  matter 
how  much  valuable  information  may  be 
gathered,  it  will  be  of  little  use  unless  it 
be  clearly  shown. 

3.  The    sketch   should   contain   all    data   of 
military  value  to  the  purposes  for  which 
it  is  needed.     It  may  be  a  model  in  its 
technique    and    yet   have    left   out    some 
feature  of  such  military  value  as  to  make 
it  of  little  or  no  use. 

4.  A  sketch  may  be  inaccurate  in  many  of 
its  measurements  and  still  be  so  clear  in 
showing  what   is   meant   and  have   such 
military  value,  that  the  inaccuracies  make 
no      difference.        Accuracy,      therefore, 
though  always  to  be  sought,  must  be  sub- 
ordinate in  a  relative  degree  to  finishing 
the  task  in  the  time  allotted,  to  clearness 
of  expression,  and  to  military  value. 


16  SKETCHING  METHODS 

The  relative  importance  of  the  foregoing 
principles  may  be  determined  in  each  case  by 
a  careful  summing  up  of  the  requirements  of 
the  situation  which  calls  for  the  sketch. 

In  the  assumed  situation  cited,  you  should 
be  able  to  determine  at  once  just  what  the 
Colonel  will  want  to  know  about  the  area  be- 
fore issuing  his  outpost  order.  You  should, 
therefore,  know  what  features  and  distances 
to  estimate  and  what  to  measure,  where  to  go 
fast  in  your  work  and  where  slow. 

Summing  up  the  situation,  you  would  real- 
ize: 

1.  That   the   Colonel   will   need   to   have   a 
sketch  of  the  whole  area  before  him; 

2.  That   the    information   contained    in   the 
sketch  must  be  so  clear  that  there  can 
be  no  mistake  about  what  is  meant; 

3.  That   all   features   which   have   value    in 
outpost  duty  should  be  especially  noted; 
for  instance,  a  hill  about  three  hundred 
yards  south  of  Y,  commanding  the  road 
from   the   enemy,   can  be   held  by   com- 
paratively   few   men.      The    strength    of 
this   position  must   be   indicated   on   the 


SKETCHING  METHODS  17 

sketch,  as  it  has  a  direct  bearing  on  the 
number  of  men  assigned  to  the  various 
sectors. 

4.  That  the  sketch  must  be  as  accurate  as 
possible,  consistent  with  (1),  (2),  and 
(3). 

There  may  arise  cases  where  the  judgment 
of  the  experienced  sketcher  will  cause  him  to 
change  the  relative  value  of  the  foregoing 
principles.  This  is  to  be  expected,  because 
each  sketch  is  a  problem  in  which  the  sketcher 
must  use  his  best  judgment  in  determining 
how  to  gain  and  to  convey  the  desired  infor- 
mation. 

The  beginner,  however,  must  learn  to  sketch 
before  he  can  pay  much  attention  to  these 
considerations.  Clearness,  accuracy,  and  speed 
in  the  order  named  should  be  his  guide  until 
he  has  attained  a  fair  ability  in  making  a 
sketch. 

The  habits  formed  in  learning  to  sketch  will 
have  a  great  influence  upon  the  speed  and  skill 
that  may  be  attained.  From  the  start,  system 
in  the  methods  of  working  should  be  prac- 


18  SKETCHING  METHODS 

ticecl.  No  one  can  become  expert  at  sketching 
unless  the  habit  of  working  systematically  is 
acquired. 

CLASSIFICATION  OF  SKETCHES. 

The  name  given  usually  indicates  the  nature 
of  the  sketch.  There  are  two  general  classes 
of  military  sketches:  (1)  area  sketches;  (2) 
reconnaissance  sketches. 

Area  sketches  are  classified  as : 

1.  Position  sketch.     This  is  a  sketch  of  an 
area  to  all  parts  of  which  the  sketcher 
has  access.     Scale  usually  6  inches  to  the 
mile;  V.  L,  10  feet. 

2.  Outpost    sketch.      In    this    the    sketcher 
travels  along  and  in  rear  of  the  outpost 
line  sketching  the  area  to  the  front.   Scale 
6  inches  to  the  mile;  V.  L,  10  feet. 

3.  Place  sketch.     The  sketcher  is  located  "in 
one  place"  on  a  hillside  or  hilltop  in  a 
restricted  area,   from  which  he  sketches 
the  area  to  the  flanks  as  well  as  to  the 
front.     Scale  6  inches  to  the  mile;  V  .  I., 
10  feet. 

Reconnaissance  sketches  are  classified  as: 


SKETCHING  METHODS  19 

1.  Road    sketch.       This    is    usually    made 
mounted.      The    sketcher    preceding    the 
column    sends    back    his    reconnaissance 
sketches  as  promptly  as  possible,  so  that 
the  commander  may  use  the  information 
contained  in  them  on  the  march  and  in 
making  his  dispositions.     Scale  3  inches 
to  the  mile;  V.  I,  20  feet. 

2.  River  reconnaissance  sketch.   This  is  usu- 
ally made  with  the   idea   of   securing  a 
special   report  of  topographical   features 
and  other  features  on  a  river  line.    Many 
of   these   cannot   be    shown   by   conven- 
tional signs  and  are  written  on  one  side 
of  the  sketch.     These  sketches  are  made 
mounted.      Scale   3    inches   to  the   mile; 
V.  I.,  20  feet. 

3.  Railroad  reconnaissance  sketch.     Similar 
to  the  reconnaissance  of  a  river.     Scale 
3  inches  to  the  mile;  V.  I.,  20  feet. 

OUTLINE  FOR  BEGINNER. 

The  following  is  a  general  outline  of  the 
successive  steps  that  may  be  taken  in  learning 
to  sketch.  It  is  inserted  here  merely  as  a 


20  SKETCHING  METHODS 

guide  to  those  who  are  taking  up  sketching 
alone  or  in  company  with  others  who  are  also 
beginners.  The  time  available  to  the  student 
must  be  used  to  the  greatest  advantage,  and 
he  alone  is  able  to  divide  it  with  that  in  view. 
For  this  reason,  the  steps  are  merely  advisory. 
All  indoor  practice  suggested  should  be  taken 
up  and  carried  on  simultaneously  with  field 
work. 

In  sketching,  as  in  any  other  art,  practice 
only  makes  perfect.  The  steps  to  be  taken  by 
the  beginner  may  be  analyzed  as  follows : 

1.  Study  the  conventional  signs  and  prac- 
tice same.      (Page  34.) 

2.  Lay  off  a  measured  ground  course  and 
practice    striding    and    counting    strides 
(double  paces.)      (Page  27.) 

3.  Practice     making     titles     for     different 
classes  of  sketches.     (Page  43.) 

4.  Determine  stride  and  construct  or  select 
scale  of  strides  for  6  inches  to  1   mile 
and  paste  on  ruler.     (Page  48.) 

5.  Take  out  board  and  practice  orienting 
by  turning  arrow  to  north  and  by  back- 
sighting.      (Page  24.) 


SKETCHING  METHODS  21 

6.  Practice  location  of  points  by  traversing 
and  intersection.      (Page  57.) 

7.  Practice  estimating  horizontal  distances 
in  units  of  100  yards.     (Page  60.) 

8.  Practice  estimating  vertical  distances  in 
units  of  10  feet.     (Page  63.) 

9.  Run  a  traverse  for  a  short  distance,  put- 
ting in  horizontal  detail  only.     Practice 
locating  points  by  traversing,   intersec- 
tion,  resection  and  estimation.      (Page 
58.) 

10.  Take   up   study   of   contours   and   prac- 
tice   logical    or   mechanical    contouring. 
(Page  69.) 

11.  Keep    up    practice    in    making    conven- 
tional    signs     by     drawing     imaginary 
countrysides.      (Page  41.) 

12.  Run  a  traverse  again  as  in  9.     Practice 
estimating   differences    in   elevation   be- 
tween  critical   points  and  noting  same. 
(Page  71.) 

1.3.  Make  two  or  three  such  traverses,  prac- 
ticing to  acquire  speed  and  method  in 
your  system  of  working.  (Page  79.) 


22  SKETCHING  METHODS 

Fill  in  only  flat  or  horizontal  detail  but 
be  particular  to  locate  the  drainage  lines. 
Practice  orienting  by  backsight  and 
checking  each  time  by  arrow  pointing  to 
north.  Put  a  title  on  each  before  con- 
sidering it  finished.  (Page  86.) 

14.  Select  an  area  *4  to  l/2  mile  square  and 
make  a  sketch  of  it.     Practice  adjust- 
ment to  close.      (Page  84.)      Show  all 
drainage  lines  clearly. 

15.  Meanwhile,     having     practiced     logical 
contouring  until  you  can  do  it   intelli- 
gently   and    rapidly,    sketch    the    same 
area  again  in  the  same  manner  as  be- 
fore, and  in  addition  estimate  and  deter- 
mine elevations  of  critical  points.     Now 
take  this  sketch  and  contour  it  by  logi- 
cal methods.      (Page  70.)      Do  this  at 
home  or  at  some  place  from  which  you 
cannot    see    the    ground    you    are    con- 
touring.    The  idea  of  this  is  to  impress 
upon  the  beginner  the  necessity  of  se- 
curing all  data  that  may  be  needed  for 
contouring  upon  one  traverse  over  the 
ground. 


'SKETCHING  METHODS  23 

16.  Make  another  sketch  of  the  same  area. 
Fill   in  flat  detail  as  you  go  and  note 
elevation  and  location  of  critical  points. 
When   you   have   the   drainage    system 
clearly   plotted,   contour   the   sketch   on 
the  ground.     Space  the  contours  accord- 
ing to  the  ground.     (Page  76.) 

17.  Make  position  sketches  of  other  areas  in 
the  same  manner  as  the  last  one.    (Page 
83.)      Never  start  contouring  until  the 
drainage  system  is  "pinned  down" ;  the 
big  features  will  then  be  seen,  and  the 
little  ones  will  take  care  of  themselves. 

18.  Make  at  least  three  outpost  sketches  and 
two  place  sketches  at  6  inches  to  the 
mile  and  10  feet  V.  I.  before  attempt- 
ing to  make  a  road  sketch.     (Page  87.) 

19.  Construct  a  scale  of  strides  for  3  inches 
to  the  mile  and  take  up  road  sketching 
dismounted.     (Page  91.) 

20.  Secure  a  mount  and  make  a  scale  read- 
ing minutes  for  trot  and  walk.     Take 
up  mounted  road  sketching.    (Page  95.) 

21.  Later  take  up  other  kinds  of  reconnais- 
sance sketching.     (Page  98.) 


24  SKETCHING  METHODS' 

SKETCHING  TOOLS. 

Sketching  board.  The  issue  sketching  board 
with  a  compass  set  in  a  trough  in  one  edge  is  a 
good  board  for  sketching.  It  has  an  attachment 
on  the  under  side  for  securing  the  tripod  to  it.  It 
is  about  13"  x  14"  which  allows  2  miles  of 
position  sketch  (6  inches  to  the  mile)  to  be 
made  with  enough  extra  space  to  secure  the 
paper  to  the  board. 

A  home-made  board  of  the  same  size  made 
of  light  wood  about  %  inch  thick,  with  holes 
in  two  diagonally  opposite  corners  for  a  rope 
by  which  to  carry  it  makes  a  very  good  sketch- 
ing board. 

A  tripod  may  be  used  but  is  not  necessary. 
When  instructing  large  classes  by  intensive 
methods  the  compass,  pace  tally  and  tripod 
should  not  be  used,  as  it  requires  too  much  time 
to  learn  their  use. 

TO  ORIENT  THE  BOARD. 

Having  tripod  and  compass.  Set  up  the  tri- 
pod with  board  loosely  screwed  on  to  it 
and  level  by  eye  by  moving  the  tripod  legs. 
Note  that  tripod  legs  are  firmly  set  so  as 


SKETCHING  METHODS  25 

not  to  slip  easily.  Free  the  needle  by  turn- 
ing the  cam  and  then  turn  the  board  slowly 
around  until  the  needle  swings  from  side 
to  side  in  the  trough.  Let  the  needle  set- 
tle, turning  the  board  so  that  when  settled 
the  needle  lies  directly  over  the  north  line 
in  the  bottom  of  the  trough.  Without  chang- 
ing the  position  of  the  board,  reach  under 
and  tighten  up  the  screw  of  the  tripod.  Care 
must  always  be  taken  not  to  turn  the  tripod 
screw  too  tight  as  the  threads  are  likely  to  be 
started  by  rough  treatment.  The  board  is  now 
oriented.  Draw  a  line  parallel  to  the  needle 
on  the  paper  and  mark  the  north  end  with  a 
half  arrow.  This  magnetic  meridian  line  is 
sometimes  marked  M.  M. 

Without  compass  and  tripod.  Draw  a  line 
parallel  to  the  edge  of  the  paper  and  place  a 
half  arrow  on  one  end  of  it.  Turn  the  board 
around  until  the  arrow  points  north  and  the 
board  is  oriented.  Use  watch  and  sun  or 
general  knowledge  to  determine  north  at  first, 
thereafter  orient  by  backsight  but  check  back- 
sight orientation  when  necessary  by  the  same 
methods. 


26  SKETCHING  METHODS 

To  Orient  the  Board  by  Backsight.  Having 
plotted  (located  and  drawn  in)  a  station  and 
arrived  at  a  point  further  on,  which  you  have 
sighted  and  drawn  a  line  to,  measure  off  the 
number  of  strides  taken  between  the  two  points 
on  your  line,  and  stick  a  pin  in  the  point  found. 
This  is  your  present  position.  Place  your  ruler 
against  the  pin  and  along  the  line  between  the 
two  points  and  turn  the  board  until  the  station 
which  you  have  just  left  is  sighted.  The  board 
is  oriented.  Verify  this  by  checking  arrow  or 
reading  the  compass  needle. 

All  of  these  methods  of  orientation  can  be 
practiced  in  a  small  space.  Set  up  the  board 
and  orient  by  compass.  Stick  a  pin  in  your 
assumed  position  and  draw  to  a  fence  post  or 
any  object,  fifteen,  twenty,  or  one  hundred 
feet  distant.  Now  move  over  to  near  the  fence 
post  and  set  up  again.  Orient  the  board  by 
arrow  and  then  verify  by  a  backsight  orien- 
tation on  the  first  station.  For  this  practice, 
a  scale  of  an  inch  to  a  few  feet  may  be  as- 
sumed, and  the  distances  measured.  In  this 
case,  practice  may  be  had  from  one  point  to 
three  others  and  then  back  to  the  first.  This 


SKETCHING  METHODS  27 

will  give  an  opportunity  to  check  the  accuracy 
of  your  orientation  by  seeing  how  well  your 
lines  close.  Intersection  and  resection  methods 
may  also  be  practiced  in  this  same  manner. 

Tally  Register  or  Pace  Tally. — This  instru- 
ment is  used  to  keep  the  record  of  the  number 
of  strides  (double  paces)  taken  in  measuring 
the  distance  between  points.  It  is  important 
that  the  number  of  strides  be  counted  as  ac- 
curately as  possible  and  for  this  reason,  the  be- 
ginner should  learn  to  register  them  auto- 
matically, that  is,  without  giving  the  act  of 
pressing  the  lever  any  attention. 

With  the  pace  tally  held  in  the  left  hand, 
finger  through  ring,  the  lever  is  pushed  down 
each  time  the  right  foot  strikes  the  ground. 
This  system  of  recording  the  strides  is  the  best 
possible,  because  the  left  hand  is  free" to  handle 
the  register  and  after  practice  will  automatic- 
ally or  subconsciously  press  the  lever  when  the 
right  foot  strikes  the  ground  which  occurs 
when  the  left  hand  reaches  the  forward  point 
of  its  swing.  The  more  nearly  automatic  the 
act  of  recording  the  strides  becomes,  the  more 


can   the   sketcher's   attention   be  given   to   ob- 


28  SKETCHING  METHODS 

serving  the  configuration  of  the  ground  and 
the  details  of  the  country  through  which  he  is 
passing. 

However,  it  is  possible  to  get  very  good  re- 
sults by  training  men  to  count  their  strides  and 
tally  every  hundred  strides  on  the  edge  of  the 
paper:  There  are  various  ways  of  counting 
and  tallying  strides  without  a  pace  tally.  After 
a  little  practice  each  individual  will  select 
his  own  way.  The  beginner  should  learn  to 
stride  at  a  uniform  gait  and  to  register  the 
strides  or  to  count  them  with  the  least  mental 
effort.  Do  not  attempt  to  take  strides  of  a 
certain  length  but  step  along  at  a  natural  gait, 
swinging  the  arms  naturally  and  keeping  the 
mind  off  of  the  counting  of  strides  or  of  their 
length.  When  walking  anywhere  by  yourself, 
practice  counting  your  strides  or  carry  the 
pace  tally  and  register  them.  If  opportunity 
offers,  do  this  in  walking  to  or  from  your 
office  or  place  of  business.  Practice  it  as 
much  as  possible,  and  you  will  soon  find  that 
the  number  of  strides  in  a  given  distance  will 
become  more  and  more  uniform.  Until  one 
learns  to  stride  naturally  and  uniformly,  the 


SKETCHJXG  METHODS  29 

stride  will  be  affected  by  walking  with  or  near 
another  person. 

Once  in  a  while,  a  tally  register  will  be 
found  which  occasionally  fails  to  register  a 
change  of  100  strides.  This  can  be  detected 
by  a  peculiar  click  when  it  happens.  The  fail- 
ure is  often  due  to  the  sketchers  not  pressing 
the  lever  down  far  enough.  The  register  can 
be  tested  indoors  by  watching  the  face  of  the 
dial  while  pressing  the  lever  and  tallying 
through  a  couple  of  hundred  counts. 

Triangular  Ruler  (fig.  2). — The  best  ruler 
for  sketching  is  one  of  triangular  shape  about  8 
inches  long  with  faces  about  0.8  inch  wide, 
with  both  ends  weighted.  Such  a  ruler  has 
been  developed  at  the  Army  Service  Schools 
and  can  be  bought  at  slight  expense  from  the 
Book  Department,  Army  Service  Schools,  Fort 
Leavenworth,  Kansas.  It  has  on  it  a  scale  of 
inches,  one  of  100  yards  at  3  inches  to  the 
mile,  and  one  of  100  yards  at  6  inches  to  the 
mile.  There  is  ample  space  left  on  which  the 
sketcher  may  paste  his  scale  of  strides  for 
sketching  at  6  inches  and  at  3  inches  to  the 
mile,  as  wrell  as  his  horse's  walk  and  trot  scale 


30  SKETCHING  METHODS 

for  mounted  work.  A  very  satisfactory  ruler 
ean  be  made  by  sawing  in  two  a  piece  of  pine 
or  other  common  wood  about  %  inch  square. 
This  makes  a  triangular  ruler  which  is  con- 
venient in  size  and  shape.  It  should  be  cut 
in  6-inch  lengths  and  should  have  on  it  the 
sketcher's  scale  of  strides,  a  scale  reading  100 
yards  at  6  and  at  3  inches  to  the  mile  and  an 
inch  scale  reading  down  to  a  10th  of  an  inch. 

When  using  the  ruler  for  sighting  an  object, 
place  one  of  the  edges  against  the  pin  in  your 
station,  sight  along  the  top  edge,  and  pivot 
the  ruler  with  forefinger  and  thumb  around 
the  pin  until  the  desired  object  is  in  line.  Then 
draw  the  ray  (light  line)  along  the  edge  of 
the  ruler  next  to  the  pin.  When  sighting  up 
or  down  a  steep  slope,  the  sketchier  may  find 
it  of  assistance  to  stick  a  pin  vertically  in  each 
end  of  the  top  edge  and  use  them  to  sight  by. 

Pencils. — A  soft  pencil,  HB  grade,  or  Eber- 
hard  Faber  No.  2  with  eraser  on  it,  should  be 
used  in  learning  to  sketch.  Harder  pencils 
will  tear  the  paper,  and  their  marks  are  so 
difficult  to  see  that  the  sketcher  is  likely  to 


SKETCHING  METHODS  31 

strain  his  eyes.  When  sheet  celluloid  is  used, 
a  2H  pencil  is  better. 

A  knife  or  a  pencil  sharpener  should  be  car- 
ried, and  the  pencils  should  always  be  kept 
sharp.  A  piece  of  emery  paper  pinned  to  the 
carrier  is  very  valuable  for  putting  on  a  fin- 
ished point. 

Eraser. — A  soft  rubber  eraser  is  a  popular 
article  in  the  equipment  of  the  beginner.  The 
Ruby,  Eberhard  Faber,  New  York,  is  a  very 
satisfactory  one.  One  on  the  pencil  will  serve, 
however,  very  nicely. 

Paper  and  Thumb  Tacks. — All  sketches 
should  be  made  on  a  tracing  paper  in  order 
that  they  may  be  blueprinted  without  the 
necessity  of  tracing  them.  For  this  reason, 
tracing  paper  should  always  be  used,  except 
in  the  earlier  practice  when  any  variety  of 
drawing  or  heavy  wrapping  paper  will  do.  It 
will  be  found  that  the  paper,  if  pinned  to  the 
board  by  thumb  tacks  some  time  before  it  is 
to  be  used,  will  bulge  up  and  have  to  be  re- 
adjusted. For  this  reason  it  is  well  not  to 
pin  your  paper  in  position  until  just  before 
starting  out.  Extra  thumb  tacks  should  be 


32  SKETCHING  METHODS 

carried.  These  may  be  stuck  on  the  under 
side  of  the  board  or  kept  in  a  piece  of  cork 
in  the  carrier. 

Large  Headed  Pins. — Several  of  these  should 
be  stuck  in  the  carrier  or  clothing  where  they 
can  be  gotten  at  conveniently.  They  are  most 
useful  in  sketching.  Common  glass-headed  pins 
about  \l/>  inches  long  with  a  head  about  1-10 
inch  in  diameter  are  best. 

Carrier. — This  can  be  made  of  canvas  or 
heavy  cloth  sewed  over  a  piece  of  light  wood 
or  heavy  cardboard,  or  they  may  be  purchased 
at  the  Book  Department,  Army  Service 
Schools  (fig  3).  The  sketcher  must  have 
every  appliance  in  its  place,  when  he  wants  to 
use  it,  and  the  carrier  offers  a  most  conven- 
ient place  for  nearly  all  of  his  tools.  The 
carrier,  however,  is  not  necessary. 

Stop  Watch  and  Note  Pad  for  Mounted 
Work  (fig.  4). — These  are  very  convenient  for 
mounted  work.  The  pad  is  divided  into 
blocks.  The  middle  line  from  the  bottom  up 
represents  the  sketcher's  route  by  minutes  and 
quarter  minutes  of  travel,  while  the  horizontal 


SKETCHING  METHODS 


33 


nr       ^^  ..,....,....£.,...     ^j^       '""Ji-'-'isSi 


.Wl-  U1E  «PX  P«P*'Por»H    c 

mlffl  1,1,1  li 


Bin 


Fia-  2L 


Fig.  3 


34  SKETCHING  METHODS 

lines  to  the  sides  represent  hundreds  of  yards 
off  from  the  sketcher's  route.  As  the  horse 
trots  along  the  road,  the  sketcher  jots  down 
on  the  pad  in  their  proper  places  the  various 
features  which  he  observes.  After  some  min- 
utes of  travel,  he  dismounts,  and,  using  these 
notes,  sketches  in  the  road  over  which  he  has 
passed.  It  is  well  in  making  notes  on  the  pad 
to  use  a  blue  pencil  for  noting  water  courses 
and  horizontal  details  and  a  red  one  for  carry- 
ing along  the  elevations.  A  pencil  with  red 
at  one  end  and  blue  at  the  other  can  be  pur- 
chased at  any  bookstore. 

CONVENTIONAL  SIGNS. 

The  conventional  signs  used  in  military 
sketching  are  illustrated  in  Field  Service  Reg- 
ulations. 

In  practical  sketching,  if  it  is  more  difficult 
or  requires  more  time  to  make  the  conven- 
tional sign  than  it  does  to  write  what  is  meant, 
the  experienced  sketcher  will  write  the  de- 
scription. 

A  sketch  is  made  primarily  to  convey  cer- 
tain information.  If  what  is  meant  to  be  con- 


• 


SKETCHING  METHODS  35 

veyed  is  not  clear  the  sketch  is  of  no  use. 
Again,  if  it  takes  a  commander  too  long  to 
read  a  sketch  he  will  blame  the  sketcher,  and 
as  his  time  will  probably  be  valuable  he  may 
not  be  able  to  take  time  to  read  it.  Always 
remember  that  the  sketch  is  being  made  to  be 
read,  that  the  convenience  of  the  reader  is 
sought,  not  that  of  the  sketcher,  that  it  is  use- 
less to  put  a  mark  on  the  sketch  unless  that 
mark  has  a  meaning  which  the  reader  will  be 
able  to  make  out. 

It  is  desirable  that  the  conventional  signs 
shall  picture  what  they  represent  as  nearly  as 
possible,  so  as  to  be  easily  interpreted ;  be  sim- 
ple in  construction  so  that  they  may  be  made 
rapidly ;  not  take  too  much  space  on  the  sketch ; 
and  that  they  be  so  clear  as  to  be  readily  un- 
derstood and  not  be  mistaken  one  for  another. 

Practice  in  rapid  work  has  developed  many 
short  cuts  in  making  them.  These  convey  the 
same  information  with  fewer  pencil  marks  and 
probably  greater  clearness  (fig.  5). 

It  is  to  be  noted  that  the  cross  marks  on  a 
railroad,  the  signs  indicating  the  different  kinds 
f  fences,  the  marks  along  a  road  indicating 


36 


SKETCHING  METHODS 


\    Cut    to'    / 


_   JVoacL  Smooth  and  Bar- 
-bed Wire  Fences.  Cut 


,\ 


T 


.*  A  H  R. 


/  (  \ 
\  Wood 
d  ^ox  go' 
r      tS7 


_   Road.  Hedge  .Fence  Tele- 
-graph.  Fill." 

_     Culvert.  Bridge  wifH 
Dimensions . 


Railroad  Ki$ht  of 
Fence  Ma\)  Be  Shown  or 
jMote  Stating  it  is  There 
I  Be  Made  in  ~ ' 


T 


_  Barbed  Wire    Fence 
Across   Countrv)  . 
Tel.  Line  Off    Road. 


vWoods    \  Area  Cov/erecl  by  Woods 


-Stream  Line  £0*  Wide 
^^^^kso'waS1  Banks  2' Deep. 
^^^^^^^b^d^  Scattered  Trees  on  a\\ 
But  one  Branch 
Broken  Line  s  no  Water 


^o 
/2> 


5tone 

I  House  6"-]  Mile 
House  3"-lMile 


Where  Area  is 
Not  Cultivated 
-"  Leave  Blank  . 


CONVENTIONAL  SIGNS 


SKETCHING  METHODS  37 

telegraph  line  and  the  T  representing  a  tele- 
graph line  across  country,  are  to  be  made  1  inch 
to  \l/2  inches  apart  on  a  scale  of  3  or  6  inches 
to  the  mile.  This  is  done  principally  for  the 
sake  of  clearness,  though  a  great  deal  of  time  is 
saved  by  it.  It  is,  however,  an  excellent  rule 
never  to  put  a  mark  on  a  sketch,  no  matter  how 
small,  that  is  not  necessary. 

A  culvert  or  bridge  less  than  10  feet  long 
(road  length)  should  be  represented  by  two 
V's  at  right  angles  to  the  road  with  the  points 
of  the  Vs  opposite  each  other.  Dimensions 
need  not  then  be  given  as  in  a  larger  bridge, 
but  the  material  and  the  condition,  if  poor, 
should  be  noted,"  "brick,  poor,"  or  "wood, 
bad." 

Roads  are  conventional  signs.  Try  and  show 
them  about  1-16  of  an  inch  wide  at  3  inches 
to  the  mile  and  about  1-10  inch  wide  at  scale 
of  6  inches  to  the  mile.  The  road  lines  should 
stand  out  clear  and  distinct  with  no  lines  or 
>ther  conventional  signs  crossing  the  road. 
Fence  and  telegraph  signs  are  placed  on  the 
gs. 


38  SKETCHING  METHODS 

A  hedge  fence  is  represented  by  drawing  H's 
across  one  of  the  road  lines  at  about  the  same 
intervals  as  fence  signs.  Fence  and  hedge 
signs  are  the  only  marks  that  should  ever 
appear  between  the  borders  of  a  road. 

Stone  and  wood  fences,  being  very  unusual 
features,  are  noted  in  sketching  by  writing  in 
"stone"  or  "wood"  along  a  line  drawn  to  rep- 
resent the  fence,  if  along  a  road  use  the  road 
line,  with  marks  indicating  the  limits  of  the 
stone  or  wood  fence.  A  marginal  note  is  sim- 
plest and  easiest. 

Signs  for  single  trees  are  drawn  oblong  in 
shape  and  about  1-10  of  an  inch  long  at  6 
and  about  1-16  inch  long  at  3  inches  to  the 
mile.  Space  them  sufficiently  to  be  distinct  so 
as  to  blueprint  readily.  Do  not  attempt  to 
show  individual  trees.  The  sign  indicates 
trees  in  that  locality. 

Houses  are  represented  by  black  blocks 
which  are  made  square  and  large  enough  to 
be  set  in  the  road  at  the  scale  being  used. 
That  will  make  the  house  sign  about  1-10 
inch  square  at  6  and  1-16  inch  square  at  3 
inches  to  the  mile. 


SKETCHING  METHODS  39 

In  order  to  proportion  the  signs  to  the  scale 
used  it  is  convenient  to  always  make  the  lines 
that  go  on  or  along  the  road  about  as  long 
as  the  road  is  wide.  This  refers  to  such  signs 
as  a  telegraph  line  along  the  road,  the  barbed 
wire  fence  lines  which  make  the  X's  on  a  road 
line  and  the  signs  for  cuts,  fills,  bridges,  cul- 
verts, etc. 

A  row  of  houses  occupying  a  certain  dis- 
tance along  a  road  need  not  be  indicated  in- 
dividually, but  houses  signs  covering  the  scale 
distance  occupied  by  them  should  be  drawn  in. 

A  dry  watercourse  should  be  indicated  by  a 
broken  line,  which  should  be  wavy  so  as  not 
to  be  mistaken  for  a  trail  sign,  which  is  a 
broken  straight  line.  If  there  is  a  small  town 
along  your  road,  do  not  attempt  in  a  road 
sketch  to  show  the  individual  streets,  alleys, 
and  houses,  but  make  a  town  sign  covering 
the  area  of  the  town,  and  write  in  its  name. 
(See  fig  1,  Town  of  Dover.) 

Where  the  conventional  sign  or  written 
words  cannot  be  put  in  at  the  place  desired 
without  excessive  crowding,  write  a  ( 1 )  at  that 
place  and  insert  description  in  a  marginal  note 


40  SKETCHING  METHODS 

opposite  a  ( 1 )  on  the  margin.  Carry  these 
marginal  notes  by  serial  numbers;  on  a  road 
sketch,  start  them  at  the  bottom  of  the  margin 
and  run  up;  on  other  sketches,  start  at  the  top 
of  the  paper  and  number  them  down. 

Break  contour  lines  on  each  side  of  a  road, 
a  conventional  sign,  or  an  abbreviation  (as  a 
description  of  a  bridge).  Never  run  them 
through. 

It  should  be  remembered  that  your  sketch, 
when  finished,  must  be  ready  for  blueprinting 
copies  without  tracing;  therefore,  all  signs 
should  be  distinct  enough  for  this  purpose.  All 
lines  should  be  firm  and  clear  cut. 

Anyone  who  has  the  ability  to  learn  to  read 
and  write,  should  be  able  to  learn  to  sketch. 
In  sketching,  as  in  writing,  however,  the  signs 
used  have  to  be  learned,  and  facility  in  making 
them  has  to  be  gained  before  much  can  be 
accomplished.  Much  time  is  wasted  in  the 
field  by  beginners  on  account  of  the  fact  that 
they  have  not  sufficient  familiarity  with  the 
conventional  signs  and  abbreviations  to  enable 
them  to  put  down  the  right  one  quickly.  No 
one  should  attempt  to  sketch  until  the  con- 


SKETCHING  METHODS  41 

ventional  signs  are  learned  and  some  facility 
in  making  them  has  been  acquired.  This  can 
be  practiced  anywhere  indoors  by  drawing  a 
skeleton  sketch  of  roads  and  stream  lines  and 
filling  in  imaginary  countrysides.  Locate  and 
draw  in  farm  houses,  orchards,  fences,  trees, 
woods,  cuts,  fills,  bridges,  unimproved  roads, 
railroads,  etc.  Form  a  general  idea  of  scale 
distances  but  make  this  practice  mainly  to  help 
you  to  learn  the  conventional  signs  so  that 
when  you  see  something  that  you  wish  to 
represent,  you  will  be  able  to  put  it  down  with- 
out having  to  stop  and  think  how  you  should 
represent  it.  It  is  splendid  practice  for  a  class 
to  have  the  instructor  dictate  to  them  a  de- 
scription of  a  countryside  which  the  students 
represent  by  conventional  signs  at  the  scale 
ordered.  The  various  features  and  objects 
are  represented  according  to  the  distance  and 
direction  as  given  by  the  instructor.  To  stim- 
ulate interest  and  note  progress  the  papers  may 
be  turned  in  and  corrected.  It  is  not  only  neces- 
sary to  know  the  sign  when  you  see  it,  but 
it  is  necessary  in  sketching  that  you  be  able 
to  make  it  quickly  and  easily.  It  should  be 


42  SKETCHING  METHODS 

easier  for  the  sketcher  to  make  the  conven- 
tional sign  than  to  write  the  words.  Practice 
of  this  kind  will  also  assist  in  overcoming  the 
diffidence  that  many  feel  about  the  mechanical 
work  of  drawing,  as  it  will  accustom  the  hand 
and  eye  to  working  with  pencil  and  ruler. 

A  familiarity  with  the  scale  distance  of  some 
commonly  used  unit  of  measure  is  essential 
to  the  sketcher  for  putting  down  distances  as 
he  estimates  them.  All  estimates  of  distance 
should  be  made  in  hundreds  of  yards;  there- 
fore the  sketcher  should  be  able  to  accurately 
lay  off  a  hundred-yard  measure  to  the  scale 
of  the  map.  As  all  work  in  learning  to  sketch 
will  be  at  6  and  3-inch  scales,  the  beginner 
should  practice,  along  with  the  making  of  con- 
ventional signs,  jotting  clown  hundreds  of 
yards  at  6  and  3  inches  to  the  mile  and  inches 
and  halves  and  tenths  of  inches.  This  can 
be  done  by  dotting  off  these  distances  any  time 
or  anywhere  and  then  checking  them  with 
these  found  on  the  triangular  ruler.  This  also 
gives  an  idea  of  what  may  be  shown  at  the 
different  scales.  At  scale  of  1  inch  to  the 
mile,  a  heavy  pencil  line  is  about  50  yards 


SKETCHING  METHODS  43 

wide;  1-10  inch  at  6  inches  to  the  mile  is  about 
30  yards ;  at  3  inches  to  the  mile,  it  is  60  yards 
and  at  12  inches  about  15  yards.  This  prac- 
tice is  most  important  for  the  beginner. 

TITLE. 

Every  completed  sketch  should  contain  a 
title,  setting  forth  the  character  of  the  sketch, 
the  sketcher's  name  and  rank,  the  locality 
sketched,  the  elate,  the  scale  (in  inches  to  the 
mile),  a  graphic  reading  scale  of  yards  and 
the  north  and  south  line  parallel  to  one  side. 

All  lettering  on  position  sketches  should  be 
written  so  as  to  be  read  from  the  south  edge. 
In  place  sketches,  it  should  be  so  located  as  to 
be  read  from  the  sketcher's  position  with  the 
sketch  oriented.  In  outpost  sketches,  the  let- 
tering is  read  facing  toward  the  enemy.  In 
road  sketches,  the  lettering  should  be  made  so 
that  it  may  be  read  by  anyone  following  the 
route  of  the  sketcher  with  the  sketch  oriented! 

Figure  6  illustrates  the  title  for  a  position 
sketch.  In  another  kind  of  a  sketch,  the 
proper  name  and  scale  is  substituted. 


44  SKETCHING  METHODS 

Printed  letters  are  so  much  clearer  than  or- 
dinary long-hand  writing  that  they  should 
always  be  used  in  the  body  of  the  sketch  and, 
where  time  permits,  in  marginal  notes.  In 
reconnaissance  sketches,  there  will  be  so  many 
marginal  notes  that  it  is  usually  impracticable 
to  print  them,  and  they  are  therefore  written 
out  in  long  hand. 

Contour  numbers  should  also  be  placed,  as 
far  as  possible,  the  same  as  the  lettering.  See 
figures  10  and  1 1. 

Time  is  saved,  and  the  chances  of  omissions 
avoided  by  blocking  out  on  heavy  cardboard 
a  completed  title  like  the  one  in  figure  6,  and 

POSITION  SKETCH 

Near  Eas+on 

By  W*Smi+h,Cap+.  ^nc/•/nf. 
May  15  1915 

6"  =  I  mile 
Yards 

IQO 20O      300      t»OO      50O      6OO      7OO     8OO 


Fig. 


SKETCHING  METHODS  45 

keeping  it  in  the  back  part  of  the  carrier. 
This  can  be  slipped  under  the  paper  on  the 
board  and  traced. 

In  a  road  sketch,  put  the  title  at  any  con- 
venient place.  In  all  other  sketches,  place  it 
so  as  to  be  read  from  the  south  edge. 

Where  the  V.  I.  used  is  different  from  that 
prescribed  in  the  normal  system  of  scales  (page 
62),  it  should  be  noted  in  the  title. 

SCALES. 

It  is  usual  in  military  work  to  speak  of  the 
scale  of  a  map  or  sketch  by  stating  the  number 
of  inches  on  it,  which  represent  one  mile  on 
the  ground.  Thus  we  say  a  certain  sketch  is 
made  on  a  scale  of  3  inches  to  the  mile,  mean- 
ing that  3  inches  on  the  sketch  represents  1 
mile  on  the  ground. 

A  scale  may  be  expressed  in  three  ways, 
any  one  of  which  is  sufficient  to  acquaint  the 
reader  with  it.  These  three  ways  are : 

1.  By  expression  in  words  and  figures:     3 
inches  equals   1  mile;  6  inches  equals   1  mile. 

2.  By  what  is  known  as  the  "Representative 
Fraction."      This    is   abbreviated   as  ."R.    F." 


46  SKETCHING  -METHODS 

• 

The  fraction  expresses  map  distance  in  its 
numerator  and  corresponding  ground  distance 
in  its  denominator.  For  example :  the  R.  F. 
of  a  map  on  a  scale  of.  3  inches  to  the  mile 

would  be  written  R.  F.  = The  numer- 

21120. 

ator  is  always  reduced  to  unity.  One  (unit  of 
measure)  on  the  map  represents  21120  (of  the 
same  units  of  measure)  on  the  ground.  The 
scale  in  inches  to  the  mile  is  readily  found  by 
dividing  the  denominator,  21120,  into  the 
number  of  inches  in  a  mile,  63360.  This  scale 
is  seldom  used  in  sketching.  Its  use  is  mainly 
in  case  of  making  a  sketch  which  may  be  con- 
verted into  some  foreign  unit  of  measure. 

3.  By  a  graphic  scale.  This  is  a  line  drawn 
on  the  map  or  sketch  and  divided  into  equal 
parts.  Each  of  these  is  marked  with  the  num- 
ber of  ground  units  it  represents.  In  our  serv- 
ice it  is  usual  to  make  these  divisions  read  miles 
and  halves  and  quarters  of  miles,  when  ex- 
pressing the  scale  graphically.  This  scale  is 
useful  on  maps  which  are  to  be  increased  or 
reduced  by  photography  on  account  of  the  fact 
that  it  will  always  read  true. 


SKETCHING  METHODS  47 

There  are  two  other  kinds  of  graphic  scales : 
Reading  and  working.  The  reading  scale  is 
made  to  read  some  well  known  and  commonly 
used  unit  of  measure,  as  feet,  yards,  etc.  In 
military  sketches  it  is  made  to  read  yards.  To 
construct  a  reading  scale  at  a  scale  of  6  inches 
to  1  mile,  lay  off  a  couple  of  inches  of  length 
and  divide  each  inch  into  three  parts.  Each 
part  will  then  represent  100  yards.  At  that 
scale  .346  inch  represents  100  yards  and  that 
is  as  near  1-3  of  an  inch  as  it  can  be  drawn 
with  an  ordinary  pencil.  After  dividing  the 
inches  into  thirds  divide  the  left  division  into 
four  parts  each  of  which  will  represent  25 
yards.  Mark  off  the  main  scale  to  read  hun- 
dreds of  yards.  For  sketching  purposes  one 
mile  may  be  said  to  contain  1800  yards.  At 
scale  of  6  inches  to  one  mile  1  inch  will  equal 
300  yards  and  1-3  inch  will  equal  100  yards. 

The  working  scale  is  made  to  read  the  units 
of  measure  used  in  making  the  sketch.  In 
sketching  this  is  usually  strides  (double  pace) 
for  dismounted  work  and  minutes  of  travel 
of  horse  at  trot  and  walk  for  mounted  work. 
The  completed  military  sketch  should  contain 


48  SKETCHING  METHODS 

the  scale  expressed  in  words  and  figures,  as  6 
inches=l  mile  and  a  reading  scale  to  read 
hundreds  of  yards.  The  working  scale  should 
not  appear  on  the  sketch. 

It  is  not  essential  that  the  sketcher  should 
have  to  do  the  mechanical  drawing  in  con- 
nection with  the  construction  of  his  working 
scale.  He  should  know  how  to  do  it  in  case 
of  need.  Scales  for  any  length  of  stride  or 
minute  scales  for  a  horse  at  trot  and  walk 
at  any  desired  scale  can  be  secured  from  the 
Book  Department,  Army  Service  Schools,  at 
Fort  Leavenworth. 

Stride  scales  for  6  inches  to  1  mile  are 
printed  in  figure  7.  They  are  placed  here  for 
convenience.  To  use  one  of  them  the  sketcher 
must  first  carefully  determine  the  length  of 
his  stride  and  either  cut  out  the  scale 
for  his  length  of  stride  or  lay  off  the 
divisions  on  another  paper  and  paste  on  his 
ruler.  Assume  that  the  average  number  of 
strides  taken  by  the  sketcher  over  a  one  mile 
measured  course  is  1048.  To  determine  the 
length  of  stride  divide  63360  (the  number  of 
inches  in  one  mile)  by  1048  and  the  quotient 


Fig.  7 


1  2  3 

i  -  1  -  1 


SCALE  OF  STRIDES 
6"  =  1  MILE 


eo  INCH  STRIDES 


1 1 1  1 1 1 1  I  I  1 1 1 1  I  I  1 1  i  I  1 1 1  1 1 1 1  1 1 1 1 1  [  I  I  1 1 1  1 1 1 1  I 

U        61   INCH   STRIDES          ^  ^  ° 

1  I  I  I  I  |  I  I  I  I  |  I  I  I  I  |  I  I  I  I  I  I  I  I  I  |  I  I  I  I  [  I  I  I  I  |  I  I  I  I  |  I  I  I  I  |  I  I  I  I  |  I  M  I  |  I  I  M  |  I 

0  62  INCH  STRIDES      2  4  6 

IJ  i  I  I  f  M  I  I  j  I  i  I  I  |  I  I  I  I  I  I  I  |  |  |  |  |  j  |  I  |  |  |  |  |  |  |  |  |  |  |  |  |  I  |  I   I  I  I  I  I  I  I  I  |  I  I  1   I  I 

"       63  INCH  STRIDES      2  4k  6 

M-l  i  I    '   I   I   i   I   |  M   I   1   j  i  i  !   |   !  I  I  1  |   |    |   I  |  I   j  I  I  I  I  |  I   1  I   I   |  I   I   I  I  |  I   I  I  I   |  I  ,   I  I   |   M   i   I 

$       64  INCH  STRIDES       2  4 

1  i  1  M  |  M  I.I  |  M  I  I  |  I  I  1  IjJ  I  I  I  |  I  I  M  |  I  MM  I  Mil  I  I  I  I  |M  M  |  I  I  I  I  U-i 
0        65  INCH  STRIDES        ^  4: 

ji  I  M  |il  H  j  Ml  I  [III  I  Jill  I  |  MM  I  Mi    |MII  I  III  II  Ml  111  II  INI 

n  <>  A 

66  INCH  STRIDES         •* 

|M  M  |  Ml  1  I  M  !  I  |l  I  I  I  M  M  I  !  !  I  1  I  II  I  II  Ml  Ml  MMI  I  Ml  |  III  I  M 

.     ! 

u        67  INCH  STRIDES 

Ml  i  I  |  I  I  I  I  |  I  I  I  I  |  I  I  I  Ml  I  I  I  |  I  I  I  I  [I  I  I  I  M  I  Ml  I  I  li-LLI  I  I  [  I  I  I  I  i 
ft          68  INCH  STRIDES         ^  4t 


I  I  I  I  I  [  i  I  M  |  I  I  I   I  |  I  I  I  I  I  I  I  I  I  |  I  I  I  I  I  I  I  I  I  |  I  I  I  M  I  I  I  I  |  I  I  I  I  |  .l.. 

^  CQ    I  M /~  u     C  -r  r%  1 1-,  cr  o  "  ^ 


M  I  i  |  I  I  I  I  |  I  I  I  I  |   M  I  I  |  I  I  I  I  }  I  I  I  I   |  I  I  1  I   |  I  I  i  I   |  I  i  I  I  |  i  1  i 
70  INCH  STRIDES          2  4 


50  SKETCHING  METHODS 

60.4  will  be  the  number  of  inches  in  one  stride. 
Select  the  scale  reading  nearest  to  the  length 
found,  in  this  case  60  inches  would  be  taken 
as  the  stride. 

Scales  constructed  by  the  student  should  be 
made  in  ink  and,  when  dry,  pasted  on  to  the 
ruler  and  later  given  a  coat  of  shellac  to  make 
them  water  proof. 

It  is  very  important  that  the  sketcher  de- 
velop a  uniform  stride  and  that  the  strides 
be  accurately  counted.  To  accomplish  this  is 
the  most  difficult  part  of  scale  making.  The 
average  number  of  strides  over  a  given  dis- 
tance must  be  fairly  uniform,  or  the  working 
scale,  no  matter  how  accurately  constructed, 
will  not  be  of  much  use. 

Every  sketcher  must  have  a  working  scale, 
constructed  to  read  strides,  at  6  inches  to  the 
mile.  Later,  one  at  3  inches  to  the  mile  for 
practice  in  road  sketching  should  be  made,  and 
when  mounted  work  is  taken  up,  a  scale  read- 
ing minutes  and  fractions  of  minutes  of  travel . 
of  the  horse  at  trot  and  walk  at  3  inches  to 
the  mile  will  be  needed. 


SKETCHING  METHODS  51 

The  making  of  a  scale  for  working  purposes 
is  simple  and  easy  enough  if  it  be  kept  clearly 
in  mind  that  it  is  merely  a  determination  ot 
the  length  that  will  be  required  to  show  a 
given  number  (usually  100)  of  strides  on  the 
ground  at  the  scale  desired. 

To  make  a  working  scale  of  strides  at  6 
inches  to  the  mile,  measure  off  with  chain  or 
tape  a  ground  course  along  a  road  or  prefer- 
ably across  country  "over  hill  and  dale"  ol 
one  mile,  three-quarters  of  a  mile,  or  one-half 
of  a  mile.  The  longer  the  course,  the  better. 
It  should  be  over  average  ground  (up  and 
down  hill)  similar  to  that  which  is  to  be 
sketched  and  should  be  carefully  measured. 

Walk  this  course  both  ways  several  times, 
counting  strides  with  the  tally  register  as  de- 
scribed under  "Tally  Register,"  or  by  counting 
and  tallying  every  100  strides  with  paper  and 
pencil.  Do  this  on  different  days  and  at  dif- 
ferent times  of  day. 

When  it  is  found  that  the  number  of  strides 
required  to  traverse  the  distance  is  fairly  uni- 
form, take  the  average  of  the  last  half  dozen 


52  SKETCHING  METHODS 

trials  to  determine  your  average  for  that  dis- 
tance. 

In  any  method  of  constructing  a  scale,  the 
above  steps  must  be  taken.  The  further  pro- 
ceedings in  the  actual  laying  off  and  marking 
off  the  scale  may  be  accomplished  in  several 
ways.  Two  ways  considered  the  simplest  and 
easiest  are  given  here. 

The  first  method  is  to  lay  off  on  your  paper 
the  scale  distance  in  inches  of  the  course  and 
divide  it  into  as  many  parts  and  fractional 
parts  as  you  have  hundreds  and  fractions  of 
hundreds  of  strides  in  your  average. 

Each  full  division  will  then  show  the  length 
on  the  working  scale  that  will  represent  100 
of  your  strides  at  the  desired  scale.  The 
fractional  division  will  represent  an  odd  num- 
ber of  strides  and  may  be  erased,  as  there  is  no 
need  for  it. 

As  an  example,  assume  that  you  find  the 
average  number  of  strides  to  cover  a  measured 
1  mile  course  is  1048.  Lay  off  a  line  6  inches 
.in  length  (the  scale  distance  for  1  mile)  and 
divide  it  into  10.48  equal  parts. 


SKETCHING  METHODS        •      53 

Each  full  division  will  show  the  distance  on 
your  working  scale  which  is  required  to  repre- 
sent 100  of  yo.ur  strides  at  a  scale  of  6  inches 
to  the  mile. 

To  complete  your  scale,  divide  the  left  one 
of  the  100  stride  divisions  into  10  equal  parts. 
This  part  of  the  scale  is  called  the  extension 
and  is  made  in  this  way  for  convenience.  Each 
of  the  10  parts  in  the  extension  represents  10  of 
your  strides.  Mark  the  dividing  line  between 
the  extension  and  the  main  scale  as  zero  and 
then  each  dividing  line  along  the  main  scale 
between  the  other  parts  with  the  number  of 
hundreds  of  strides  it  measures  from  the  zero 
mark. 

It  should  be  remembered  that  when  this 
method  is  used,  the  line  to  be  divided-  in  mak- 
ing a  scale  corresponding  to  6  inches  to  the 
mile  must  be  the  same  proportional  part  of  6 
inches  that  the  course  on  which  the  average 
number  of  strides  was  secured,  is  of  1  mile. 
That  is,  if  the  course  is  1  mile,  lay  off  6  in- 
ches; if  it  is  24  of  a  mile,  lay  off  (%of  6  in- 
ches) 4l/2  inches;  and  if  the  course  is  l/2  mile, 
lay  off  (J/2  of  6  inches)  3  inches. 


54  SKETCHING  METHODS 

The  second  method  is  to  ascertain  the 
length  in  inches  or  fractions  of  an  inch  which 
will  represent  100  of  your  strides.  Having 
this,  lay  off  the  number  of  divisions  of  that 
length  desired,  mark  them  and  paste  them  on 
the  ruler.  For  example :  Assume  that  the 
average  number  of  strides  to  1  mile  is  1048. 
It  is  desired  to  construct  a  working  scale  at 
6  inches  to  1  mile.  Divide  6  by  10.48  and  the 
result,  (.572  inches)  will  be  the  length  on 
your  working  scale  which  will  represent  100 
of  your  strides  at  6  inches  to  1  mile. 

With  a  scale  of  equal  parts  (one  reading 
inches  and  tenths  of  inches  will  serve),  lay  off 
as  many  divisions  .572  inches  long  as  you  may 
desire  in  your  scale,  and  each  of  them  will 
represent  100  of  your  strides  at  6  inches  to 
the  mile.  Mark  off  the  extension  and  the 
main  scale  as  previously  described,  trim  to  suit, 
and  paste  on  ruler. 

When  a  scale  of  strides  for  6  inches  to  the 
mile  has  been  made,  all  that  is  necessary  to 
construct  one  at  3  inches  to  the  mile,  is  to 
take  off  on  a  piece  of  paper  the  divisions  on 
the  6-inch  scale  and  mark  them  with  just 


SKETCHING  METHODS  55 

twice  the  value  they  have  at  the  6-inch  scale. 
Each  division  of  the  extension  will  represent 
20  strides  at  3  inches  to  the  mile. 

Either  of  the  foregoing  methods  may  be 
used  in  constructing  a  time  scale  for  a  horse. 
It  is  first  necessary  that  the  horse  should  be 
trotted  and  walked  several  times  over  a  course 
and  his  average  time  of  travel  secured.  In 
doing  this,  care  should  be  exercised  that  the 
horse's  gait  is  not  influenced  by  the  presence 
of  another  horse,  the  fact  that  the  animal  is 
tired  or  fresh,  that  he  is  going  towards  or 
away  from  the  stable,  etc.  Allowances  must 
be  made  for  such  things,  and  practice  enough 
should  be  had,  before  constructing  the  scale,  to 
enable  the  sketcher  to  determine  pretty  well 
whether  or  not  the  horse  is  taking  a  uniform 
gait. 

Working  scales  should  be  tested  from  time 
to  time  by  the  sketcher  in  order  to  be  sure  that 
his  stride  is  not  changing.  This  can  be  done 
by  occasionally  checking  traverses  with  a  Geo- 
logical Survey  Map  or  by  measuring  with 
chain  and  tape  some  of  the  distances  traversed. 


56  SKETCHING  METHODS 

WHAT  A  SKETCH  SHOULD  SHOW 

Broadly  speaking,  a  military  sketch  should 
show  all  natural  and  artificial  features  of  the 
surface  of  the  earth  in  the  area  sketched.  The 
magnetic-meridian  line,  a  title  giving  the  char- 
acter of  the  sketch,  the  locality  sketched,  the 
date,  the  sketcher's  name,  the  scale  of  the 
sketch,  and  a  graphic  scale  reading  hundreds  of 
yards  should  also  be  shown. 

Natural  features  (bodies  of  water,  woods, 
etc.)  and  all  "works  of  man"  are  represented 
by  conventional  signs,  drawings  to  scale,  or 
by  written  words. 

The  configuration  of  the  ground  is  repre- 
sented by  contours  showing  elevations  and  de- 
pressions with  the  character  of  their  slopes 
and  relative  heights  as  truly  as  the  scale  of 
the  sketch,  the  time  allowed  and  the  sketcher's 
ability  will  permit. 

All  detail,  except  that  shown  by  contours,  is 
called  flat  or  horizontal  detail.  That  shown  by 
contours  is  called  vertical  detail.  The  military 
sketch  must  have  every  feature  located  in  its 
relative  horizontal  and  vertical  position. 


SKETCHING  METHODS  57 

HORIZONTAL  DETAIL 

The  horizontal  position  of  any  point  is  de- 
termined when  its  direction  and  distance  from 
a  previously  determined  point  are  shown.  The 
vertical  position  is  determined  when  its  eleva- 
tion with  reference  to  an  assumed  level,  called 
a  datum  plane,  is  shown. 

The  line  from  which  all  directions  are  meas- 
ured is  the  plane  of  the  magnetic  compass 
needle,  called  the  magnetic  meridian.  The  true 
north  and  south  line  (true  meridian)  need  not 
be  considered  in  sketching.  It  is  most  import- 
ant when  direction  lines  from  one  point  to 
another  are  located,  that  the  sketching  board 
be  "oriented"  (explained  under  "Sketching 
Board").  The  sketcher  should  therefore 
always  verify  the  position  of  the  needle  or  of 
the  arrow  on  his  board  before  drawing  a  ray 
(light  line)  toward  the  object  whose  direction 
is  being  determined. 

The  position  of  a  point,  with  reference  to 
direction  and  distance,  is  determined  in  one  of 
the  following  ways :  (1)  traversing;  (2)  in- 
tersection; (3)  resection;  (4)  estimation. 


58  SKETCHING  METHODS 

Traversing 

By  this  is  meant  the  measurement  of  the 
distance  between  two  points  by  counting*  the 
strides  or  time  of  travel  required  to  pass  from 
one  to  the  other. 

The  term  traverse  is  applied  to  the  route 
followed  by  the  sketcher,  in  making*  the  sketch. 

To  locate  a  point  by  traversing. — Being  at 
point  A  (whose  position  is  plotted  on  your 
sketch)  with  the  board  oriented,  stick  a  pin  in 
point  A,  on  the  sketch.  Lay  ruler  alongside 
the  pin  and  pivot  it  around  until  point  B 
(the  point  to  which  you  are  to  traverse)  is 
sighted.  Verify  the  position  of  the  arrow  and 
then  draw  a  ray  toward  B.  Move  to  B,  count- 
ing strides,  and  upon  arrival  lay  your  ruler 
along  the  ray  with  the  zero  of  scale  of  strides 
at  A  and  lay  off  on  the  ray  the  number  of  strides 
that  you  took  between  the  two  points.  The 
point  marked  is  B. 

Intersection 

The  position  of  a  point  is  determined  in  this 
method  by  drawing  rays  toward  it  from  each 
of  two  other  points  whose  positions  are  already 


SKETCHING  METHODS  59 

determined  and  plotted  on  the  sketch.  The  in- 
tersection of  the  two  rays  is  the  sketch  posi- 
tion of  the  point  sighted. 

To  locate  the  position  of  a  point  by  intersec- 
tion.— Assume  that  from  point  A,  with  your 
board  oriented,  you  took  a  careful  sight  and 
drew  a  ray  toward  a  church  a  few  hundred 
yards  off  to  the  side.  After  arriving  at  B  and 
plotting  its  position,  you  carefully  orient  the 
board  by  a  backsight  on  A.  Pivot  the  ruler 
around  the  pin  in  B  until  the  church  is  sighted, 
then  draw  a  ray  toward  the  church.  The  inter- 
section of  this  ray  with  the  one  you  drew 
from  A  is  the  sketch  position  of  the  church. 

Resection 

This  is  determining  the  sketcher's  position 
by  orienting  the  board  and  drawing  rays 
toward  himself  from  two  or  more  points 
whose  positions  are  already  determined  and 
plotted. 

To  locate  position  b\  resection. — After  hav- 
ing plotted  the  position  of  points  A  and  B, 
the  sketcher  comes  into  his  area  later  at  some 
point  from  which  those  two  points  can  be 


60  SKETCHING  METHODS 

seen.  His  present  position  is  not  yet  deter- 
mined. To  determine  it,  set  up  the  board  and 
orient  as  carefully  as  possible  by  the  arrow, 
then  stick  pins  in.  the  sketch  positions  of  points 
A  and  B.  Pivot  the  ruler  around  the  pin  at 
A  on  the  sketch  until  you  sight  A  on  the 
ground  and  after  verifying  the  position  of  the 
arrow,  draw  a  ray  toward  yourself.  Next 
pivot  the  ruler  around  the  pin  at  B  on  the 
sketch  until  you  sight  B  on  the  ground,  and 
after  glancing  at  arrow,  draw  a  ray  from  that 
point  towards  yourself.  The  intersection  of 
the  two  rays  is  the  sketcher's  position. 

There  are  other  methods  of  resection,  but 
their  use  is  so  exceptional  that  they  need  not 
be  considered. 

Estimation 

After  some  practice,  points  nearby  are  located 
very  accurately  by  simply  estimating  their  dis- 
tance and  plotting  their  position  on  a  ray 
drawn  toward  them.  Advantage  is  taken  of 
any  feature  in  the  locality  that  may  assist  in 
determining  the  distance,  such  as  telegraph  or 
telephone  poles,  fence  posts,  section  lines,  etc. 
The  ability  to  estimate  distances  should  be 


SKETCHING  METHODS  61 

cultivated  at  every  opportunity.  A  good 
sketcher  must  be  able  to  estimate  with  less 
than  10  per  cent  error  up  to  about  300  yards 
and  within  20  per  cent  up  to  a  mile.  This 
ability  can  only  be  acquired  by  constant  prac- 
tice and  by  verifying  the  estimates  by  meas- 
urements. All  estimates  should  be  made  in 
yards,  and  100  yards  should  be  definitely  fixed 
in  mind  as  a  reference  unit. 

Do  not  estimate  on  main  traverse. 

VERTICAL  DETAIL 

The  U.  S.  Geological  Survey  uses  sea  level 
as  datum  plane  in  determining  elevations  of 
points. 

In  military  sketches,  the  area  is  compara- 
tively so  small  that  the  datum  plane  used  is 
immaterial.  The  reason  for  this  is  that  what 
is  desired  is  the  elevation  of  the  different 
points  in  the  area  with  relation  only  to  the 
other  points  in  it.  It  is  immaterial  whether 
the  elevation  of  the  starting  point  is  assumed 
to  be  500  feet  or  1000  feet,  but  all  other 
points  must  then  show  their  elevation  with 
reference  to  the  assumed  one. 


62  SKETCHING  METHODS 

It  is  well  to  ascertain  the  Geological  Survey 
elevation  of  some  point  and  start  from  there, 
because  the  sketch  can  be  checked  against  a 
Geological  Survey  Map  more  conveniently 
when  the  elevations  are  the  same,  but  it  is  not 
at  all  necessary  that  this  be  done. 

Under  our  normal  system  of  scales  the  ver- 
tical interval  (V.  I.)  used  on  military  maps  and 
sketches  can  be  found  by  dividing  the  number 
of  inches  representing  one  mile  in  the  scale  into 
60.  For  example,  at  6  inches  to  1  mile  the  V.  I. 
is  10  feet.  At  3  inches  it  is  20  feet  and  at  12 
inches  to  1  mile  the  V.  I.  is  5  feet. 

The  vertical  position  of  a  point  is  located 
by  determining  its  elevation  above  or  below 
some  other  point  whose  elevation  has  already 
been  determined. 

The  determining  of  difference  of  elevation 
of  two  points  by  estimation  is  the  method  of 
the  experienced  and  rapid  sketcher.  After 
some  time  and  with  considerable  practice,  the 
sketcher  acquires  ability  to  estimate  differences 
with  great  accuracy. 

There  are  many  ways  in  which  practice  in. 
estimating  elevations  may  be  had.  The  ability 


SKETCHING  METHODS  63 

to  strike  one's  own  level  is  of  great  value. 
This  can  be  practiced  indoors  by  swinging  the 
extended  arm  around  with  the  hand  at  level 
of  the  eye,  so  that  the  line  of  sight  over  the 
back  of  the  hand  passes  through  marks  made 
upon  the  wall  at  the  exact  height  of  the  eye. 

Having  learned  to  strike  your  own  level, 
practice  estimating  distances  or  objects  above 
and  below  this  plane  by  comparison  with  the 
heights  of  ordinary  objects  in  the  vicinity, 
such  as  telegraph  poles,  trees,  etc.  Fix  in  mind 
a  10- foot  unit  and  apply  this  to  the  height  be- 
ing determined. 

In  connection  with  estimating  either  hori- 
zontal or  vertical  distances,  it  is  well  for  the 
beginner  to  remember  that  it  is  fatal  to  good 
estimation  to  depend  upon  his  judgment  until 
he  has  a  definite  and  clear  idea  of  what  the 
units  of  measure  he  is  using  really  are,  and 
hence  he  should  if  possible  check  all  estimates 
until  he  has  attained  the  ability  to  estimate 
with  a  minimum  of  error.  This  will  come 
only  with  practice  and  constant  checking. 


64  SKETCHING  METHODS 

Contours 

The  representation  of  vertical  distances  by 
means  of  contours  seems  hard  to  the  beginner. 
This  is  largely  due  to  the  fact  that  the  average 
beginner  usually  attempts  to  contour  before  he 
really  knows  what  a  contour  is,  what  laws 
govern  their  making,  or  what  may  be  shown 
by  them  at  the  scale  being  used.  Before  at- 
tempting to  do  any  contouring,  in  the  field, 
the  beginner  should  gain  a  clear  idea  of  these 
things  by  careful  study  and  much  practice,  so 
that  when  he  takes  up  contouring  he  will 
know  what  he  is  trying  to  do. 

Contours  are  lines  drawn  on  a  map  or 
sketch,  which,  following  the  various  levels  at 
fixed  vertical  intervals,  indicate  the  shape  of 
the  ground  and  show  its  vertical  irregularities. 

The  general  laws  governing  the  use  of  con- 
tours may  be  fully  learned  only  by  actual  field 
work.  Some  are  noted  here: 

1.  Every  contour  line  either  closes  on  it- 
self or  both  ends  of  it  go  off  the  sketch. 

2.  Every  part  of  a  contour  line  is  at  the 
same  level. 


SKETCHING  METHODS  65 

3.  A  contour  about  to  cross  a  stream  line 
runs  up  on  one  side  of  the  stream  and  comes 
down   on    the   other,    making   a   V    where    it 
crosses.     The  apex  of  the  V  points  upstream. 

4.  Contours    representing    spurs    between 
streamlines  are  generally   U-shaped  with  the 
bottom   or   rounded   part   of   the   U   pointing 
down  hill. 

5.  Valley  contours  apparently  go  in  pairs; 
that  is,  the  contour  next  to  the  streamline  on 
one  side,  is  the  same  contour  as  the  one  next 
to  the  streamline  on  the  opposite  side.     If  you 
cross  the  800- foot  level  just  before  you  wade 
into  a  stream,  you  must  cross  that  same  level 
again  when  you  wade  out  on  the  opposite  side. 

6.  Ridge   contours   also   apparently   go    in 
pairs.     The  contour  next  to  the  top  of  a  ridge 
has  its  mate  next  to  it  just  over  the  ridge. 

7.  In  the  case  of  the  contours  on  opposite 
sides  of  the  stream,  their  meeting  point  will 
generally  be  found  close  by;  in  those  next  to 
the  ridge  top,  it  may  be  that  they  do  not  join 
up  on  the  sketch,  but  if  the  area  were  extend- 
ed, their  meeting  point  would  be  found  sooner 
or  later. 


66  SKETCHING  METHODS 

In  sketching,  do  not  attempt  to  show  a  cliff 
by  contours.  Break  the  contour  lines  on  each 
side  and  write  "Cliff  60'  "  (or  whatever  its 
height  may  be).  Do  the  same  with  a  bluff 
which  is  so  high  and  steep  as  to  make  diffi- 
cult clear  representation  by  means  of  contours. 
If  you  have  a  depression  to  represent,  be  sure 
that  the  contours  showing  it  are  clearly  num- 
bered so  that  it  may  at  once  be  understood. 

Detail  Shown  by  Contours 

The  amount  of  detail  that  may  be  shown 
by  contours  depends  directly  upon  the  scale  of 
the  sketch.  Failure  to  realize  this  is  one  of 
the  reasons  why  the  representation  of  ground 
forms  by  contours  is  often  difficult  for  the 
beginner.  For  example,  on  a  scale  of  3  inches 
to  the  mile,  a  spur  100  feet  long  jutting  out 
from  a  hillside  would  cause  a  contour  line  to 
change  about  1-20  inch,  the  scale  width  of  the 
spur.  If  trouble  were  taken  to  change  an 
otherwise  regular  contour  to  indicate  this,  no 
one  would  notice  it  nor  care  anything  about  it 
if  it  were  noticed.  It  is  true  that  this  spur 
might  furnish  cover  to  a  number  of  the  enemy, 


SKETCHING  METHODS  67 

but  when  the  commander  wants  a  sketch  in 
which  such  cover  becomes  important,  he  will 
have  it  made  on  a  larger  scale. 

The  minimum  size  of  ground  features  that 
can  be  shown  to  advantage  to  the  scale  used, 
should  be  determined  and  kept  clearly  in  mind 
by  the  sketcher.  Then  so  far  as  anything 
smaller  is  concerned,  he  should  regard  the 
ground  as  smooth  and  regular.  This  will 
greatly  simplify  his  work. 

It  must  be  realized  that  any  details  that  can- 
not be  shown  clearly  and  naturally  to  the  scale 
ordered,  are  not  wanted.  This,  of  course, 
refers  only  to  those  features  that  are  to  be 
shown  to  scale.  Houses,  bridges,  roads, 
streamlines,  etc.,  being  represented  by  conven- 
tional signs,  are  riot  drawn  to  scale. 

A  good  method  to  follow  to  gain  an  idea 
of  what  can  be  shown  at  the  various  scales  by 
contours  is  to  take  a  map  or  sketch  of  an  area 
and  carefully  study  the  ground  represented 
and  note  the  smaller  details  that  are  not  shown 
on  the  map.  Compare  map  and  ground,  again 
noting  carefully  the  ground  forms  as  they  are 


68  SKETCHING  METHODS 

on  the  ground  and  then  how  they  are  repre- 
sented on  the  map. 

A  box  filled  with  sand,  called  a  sand  table, 
is  a  great  aid  in  studying  ground  forms  and 
may  be  used  if  time  permits  and  outdoor  work 
cannot  be  done.  Many  exercises  can  be  held 
in  which  much  can  be  accomplished  in  learn- 
ing how  to  contour.  Make  a  mound,  assume  a 
scale,  and  represent  it  by  contours.  After 
drawing  in  the  flat  detail  of  a  sand-table 
terrain,  contour  the  area,  first  determining  the 
elevation  of  the  critical  points,  then  spacing 
the  contour  points  by  eye  according  to  the 
slopes,  and  then  connecting  up  the  levels. 

Take  a  section  of  a  contoured  map  and  repro- 
duce it  on  the  sand  table  according  to  scale. 
Later,  without  looking  at  the  contoured  map, 
make  a  sketch  of  the  area  and  compare  it 
with  the  contoured  map. 

Any  ground  forms  can  be  produced  and 
their  contour  lines  studied  out  and  drawn. 
The  amount  of  work  that  can  be  done  on  the 
sand  table  depends  upon  the  time  the  student 
will  give  to  it  and  his  ingenuity. 


SKETCHING  METHODS  69 

The  value  of  the  sand  table  is,  of  course, 
limited  to  giving  a  thorough  understanding  of 
ground  forms  and  of  their  representation  by 
contour  .lines.  This  understanding  is  essential 
to  the  sketcher.  Practical  familiarity  with 
ground  forms  and  ability  to  represent  them 
correctly  can  only  be  gained  on  the  ground, 
for  the  only  way  in  which  the  ground  perspec- 
tive can  be  appreciated,  is  by  study  of  the 
ground  itself.  To  the  beginner,  ground  dis- 
tances appear  greater  and  features  nearby 
larger  than  they  actually  are,  and  this  can  only 
be  corrected  by  actual  work  on  the  ground. 

Logical  Contouring 

The  Engineer  Department  at  the  Army 
Service  Schools  at  Fort  Leavenworth  has  had 
printed  a  number  of  plates  for  the  purpose  of 
practice  in  drawing  contours.  These  show 
the  flat  details  of  the  area  and  the  elevations 
of  critical  points.  The  entire  series  should  be 
filled  in  by  every  beginner  and  corrected  by  an 
instructor  before  attempting  any  field  work 
other  than  filling  in  flat  details.  The  series 
consists  of  several  sheets,  each  with  four  areas. 


70  SKETCHING  METHODS 

These  can  be  secured  at  small  cost  from  the 
Book  Department,  Army  Service  Schools. 
Too  much  of  this  practice  cannot  be  had.  The 
method  of  filling  in  the  contours  is  illustrated 
in  Figs.  8,  9,  10  and  11. 

Practice  in  logical  contouring,  as  it  is  called, 
is  most  necessary  to  a  clear  understanding 
of  contouring  in  sketching.  The  more  of  it  a 
student  does  the  better.  Anyone  can  make  up 
a  framework,  similar  to  those  shown  in  Figs. 
8,  12  and  13,  and  practice  contouring  by  logi- 
cal methods. 

The  procedure,  as  shown,  is  to  first  note  the 
elevations  of  critical  points  along  stream  lines 
and  ridges,  then  divide  up  and  mark  crossing 
points  of  contour  lines  along  the  main  stream 
line,  then  along  the  tributary  streams,  mark- 
ing those  on  stream  lines  with  a  V  pointing 
upstream,  then  from  points  along  the  stream 
lines  to  ridge-line  points  nearby,  mark  (with 
dots  or  short  lines)  the  crossing  points  of  the 
number  of  contour  lines  that  go  between,  ac- 
cording to  the  elevations  of  the  top  and  bot- 
tom points.  Finally,  having  enough  of  these 


SKETCHING  METHODS  71 

to  shape  the  ground,  join  them  up  by  long 
curving  lines. 

On  all  sketches,  the  contour  lines  should  be 
numbered  so  that  the  elevation  of  any  one  of 
them  can  be  readily  found.  They  should  be 
numbered  where  they  leave  the  area  and  occa- 
sionally along  a  stream  line  or  on  some  of  the 
longer  slopes  (fig.  11).  The  completed  sketch 
should  have  each  50  or  100  foot  contour  line 
drawn  heavier  than  the  others. 

Contour  Framework 

Critical  points  are  those  at  which  an  abrupt 
change  in  direction  or  slope  takes  place,  such 
as  bends  in  roads  or  streams,  stream  junc- 
tions, tops  of  ridges,  hills,  etc.  Any  feature 
which  may  assist  the  sketcher  in  securing  his 
framework,  may  be  called  a  critical  point. 

Manifestly,  it  is  impracticable  to  determine 
the  exact  location  of  the  crossing  points  of 
each  contour  line  between  all  the  critical 
points.  It  is  equally  impracticable  to  deter- 
mine the  location  of  every  slight  change  of 
slope  on  a  hillside.  Such  detail  is  not  im- 
portant and  is  not  wanted.  Hence,  the 


72 


SKETCHING  METHODS 


Fig.  8 


Arrow  heads  on  Figr.  8  snow  direction  of  water  flow 
Place  10'Contours  on  the  above  sketch  . 


Arrow  points  on  Fig.  9  [except  those  also  appearing  on  Fig.  8]  are  points 


SKETCHING  METHODS    .  73 


Fig.  JO 


Fig.ll 


74  SKETCHING  METHODS 

sketcher  ascertains  the  elevation  of  critical 
points,  thus  locating  the  position  of  the  form- 
controlling  contours  and  interpolates  the  con- 
tour lines  between  them,  spacing  by  eye  to 
indicate  the  change  of  slope  as  these  changes 
appear  to  him. 

The  undulations  and  vertical  distances  in 
the  form  of  the  ground  are  largely  caused  by 
the  erosive  action  of  rainfall,  hence  the  drain- 
age system  and  ridge  lines  form  the  frame- 
work on  which  contours  are  hung. 

If  the  sketcher  determines:  (1)  the  eleva- 
tion of  the  main  stream  line  at  the  point  where 
it  enters  his  area;  (2)  the  elevation  of  its 
junction  with  its  tributaries,  in  the  area; 
(3)  the  elevation  of  the  main  stream  where  it 
leaves  the  area :  he  will  have  a  good  base  from 
which  to  build  up  his  contours.  If  while  de- 
termining the  above,  he  also  determines  the 
elevations  of  the  tops  of  the  ridge  lines  be- 
tween the  stream  branches  and  of  important 
points  along  and  on  these  ridges,  he  will  have 
the  highest  as  well  as  the  lowest  levels  in  the 
area  and  need  only  fill  in  the  contours  between 
the  points  whose  elevations  are  known. 


SKETCHING  METHODS 


75 


The  foregoing  is  exactly  what  the  sketcher 
must  do  in  contouring.  As  he  goes  over  his 
area,  drawing  to  scale  the  flat  or  horizontal 
details,  he  locates  all  critical  points  and  esti- 
mates and  notes  their  elevation.  Then,  having 
enough  of  the  drainage  system  and  ridge  lines 
"pinned  down"  to  enable  him  to  show  the  big 
features,  he  dots  in  the  level  lines  at  their 


76  SKETCHING  METHODS 

proper  vertical  intervals  between  critical  points 
according  to  the  slope  of  the  ground.  Finally, 
he  connects  up  the  clotted  points  by  contour 
lines,  each  running  through  the  dots  of  its 
own  elevation. 

In  reality,  contour  lines  in  sketching  are 
nothing  more  than  conventional  signs.  A 
sketcher  will  soon  find  that  every  slope  is  one 
of  three  kinds,  uniform,  concave,  or  convex. 
When  spacing  in  contours,  this  should  be  kept 
in  mind.  Any  slope  of  ground  may  be 
divided  into  sections,  each  of  which  may  be 
represented  by  one  of  the  three  kinds  men- 
tioned. Practice  alone  will  enable  one  to  pick 
out  the  dividing  lines,  but  they  should  be 
looked  for  from  the  beginning. 

Where  the  slope  is  uniform,  space  your  con- 
tours equal  distances  apart;  where  the  slope  is 
concave  in  form,  space  your  contour  lines 
closer  together  near  the  higher  elevation  and 
wider  apart  toward  the  lower;  where  the  slope 
is  convex,  space  them  wider  at  the  higher  and 
closer  at  the  lower  elevation. 

The  beginner  must  learn  to  consider  general 
knowledge  of  country,  of  rates  of  fall  of 


SKETCHING  METHODS 


77 


streams,  of  railroad  grades,  and  of  ground 
forms  in  order  to  keep  his  work  logical  and 
consistent.  For  instance,  large  rivers  have  a 
fall  of  only  a  few  inches  to  the  mile,  unless 
there  are  many  rapids;  therefore,  within  the 
limits  of  an  ordinary  reconnaissance  sketch,  a 
large  river  is  at  the  same  level,  for  purposes 

IOQOJ  |          ? A,sa*     J. 7 bgj I  [i030 


.000]  [ 


Interpolate  lO'Contours. 


78  SKETCHING  METHODS 

of  determining  elevations.  A  stream  line 
carrying  water  all  the  year  round  has  a  less 
fall  per  mile  than  one  in  the  same  area  which 
is  dry  part  of  the  time.  Tributary  streams 
have  a  greater  fall  than  main  stream  lines. 
The  nearer  the  stream  to  the  source,  the 
steeper  it  falls. 

NOTES  FOR  FIELD  WORK 

Avoid  complicated  and  cumbersome  methods. 

Always  use  the  simplest  and  most  common- 
sense  way. 

Do  everything  possible,  consistent  with  re- 
quirements of  making  the  sketch,  to  save  time. 
When  you  halt  to  make  a  note,  make  it,  and 
go  on.  When  you  halt  to  fill  in  something 
and  it  is  not  necessary  to  orient,  do  not  orient 
but  do  the  filling  in  quickly,  and  move  on. 

Never  orient  the  board  unless  there  is  neces- 
sity for  it. 

Every  time  you  orient  the  board  by  arrow 
or  compass,  verify  it  by  a  backsight,  if  prac- 
ticable. Every  time  you  orient  by  a  backsight, 
verify  it  by  the  arrow  or  compass. 


SKETCHING  METHODS  79 

Always  verify  the  orientation  just  before 
you  draw  a  ray  either  along  a  traverse  or  in 
intersection  or  resection. 

Try  to  acquire  the  habit  of  doing  the  neces- 
sary things  at  each  halt  in  the  same  sequence. 
For  example,  traversing  along  a  road,  you 
arrive  at  the  top  of  a  rise,  to  which  you  had 
drawn  a  ray.  Halt  there,  look  around,  and 
select  the  best  position  for  sighting  forward 
on  the  traverse.  Lay  the  board  down  on  the 
ground  or  place  it  on  your  knees.  Take  out 
ruler  and  pencil,  and  placing  ruler  alongside 
the  ray  with  edge  of  working  scale  next  to  it, 
measure  off  the  number  of  strides  from  last 
station  and  mark  with  pencil  dot.  Stick  a  pin 
in  this  dot  which  is  your  present  station.  Lay 
ruler  along  ray  to  last  station  and  orient  board 
by  backsight.  Having  the  board  oriented, 
pivot  the  ruler  around  the  pin  and  draw  a  ray 
to  the  next  station.  Now  sight  and  draw  rays 
to  such  points  as  you  may  have  drawn  rays  to 
from  previous  station,  to  complete  their  loca- 
tion by  intersection  and  then  draw  rays  to 
such  new  points  as  in  your  judgment  may  be 
of  use,  noting  in  each  case  the  object  sighted. 


80  SKETCHING  METHODS 

Verify  orientation  each  time  before  drawing 
ray.  Now  draw  in  the  other  road  line  (the 
ray  taken  to  this  station  is  one)  and  fill  in 
the  flat  details,  houses,  bridges,  stream  lines, 
fence  signs,  etc.,  from  the  last  station  to  your 
present  one.  Determine  the  elevation  of  youi 
present  station  by  estimating  the  difference  be- 
tween it  and  the  previous  one.  In  the  same 
manner  determine  the  elevation  of  any  critical 
points  that  you  may  have  noted  in  your 
traverse  from  last  station  as  well  as  of  points 
located  by  intersection.  If  you  have  enough 
data  to  enable  you  to  contour  between  stations, 
do  it  now;  if  not,  be  sure  that  the  elevations  of 
critical  points  are  noted.  Put  the  ruler,  pencil, 
eraser,  pin,  etc.,  in  their  proper  places,  pick  up 
the  board,  and  start  traverse  to  next  station. 

The  operations  noted  in  the  foregoing  have 
to  be  carried  out  at  each  station.  Failure  to 
carry  them  out  in  sequence  while  learning  to 
sketch  will  handicap  the  beginner  very  much. 
It  is  therefore  considered  essential  that  the 
beginner  should  learn  to  do  them  in  the 
sequence  described.  After  a  while  he  will  de- 
velop the  simplest  and  best  way  for  himself. 


SKETCHING  METHODS  81 

Have  your  sketch  completed  up  to  your 
station  before  moving  on.  In  the  earlier 
stages,  this  applies  only  to  flat  details,  later  to 
both  horizontal  and  vertical  detail  in  road 
sketching  and  to  horizontal  detail  and  the  loca- 
tion and  determination  of  the  elevation  of  crit- 
ical points  in  making  a  position  sketch.  The 
contouring  in  this  case  is  not  undertaken  until 
the  entire  framework  of  ridge  and  stream  lines 
is  "pinned  down." 

Be  particular  that  the  information  conveyed 
is  not  misleading.  It  is  better  to  leave  a  part 
blank  than  to  deceive  or  mislead. 

Try  to  put  equal  care  and  time  on  all  parts 
of  the  sketch.  Avoid  excessive  care  at  the 
beginning  followed  by  excessive  haste  near  the 
end. 

Acquire  method  and  system  in  your  sketch- 
ing and  the  rest  will  be  easy. 

POSITION  SKETCH 

It  is  assumed  that  before  undertaking  to 
make  a  position  sketch,  the  sketcher  has  fol- 
lowed out  the  course  of  study  outlined  herein. 

Select  an  area  of  ground  about  one-half  a 


82  SKETCHING  METHODS 

mile  square.  One  having  roads  on  all  sides 
is  better,  but  this  is  not  material. 

Determine  where  to  locate  your  starting- 
point  on  the  paper  by  estimating  the  direc- 
tion from  you  in  which  the  area  to  be 
sketched  lies.  If  you  are  at  the  southwest  cor- 
ner of  the  area,  locate  your  starting  point  (by 
sticking  in  a  pin)  about  5  inches  from  the 
west  edge  and  5  inches  from  the  south  edge 
of  the  paper.  Since  the  area  to  be  sketched 
will  occupy  about  3  inches  square  when  drawn 
to  scale,  you  will  thus  have  it  at  about  the  cen- 
ter of  the  sheet. 

Draw  the  magnetic  meridian  line  parallel  to 
the  edge  of  the  paper,  then  orient  board.  Take 
forward  sight  to  next  station  and  draw  ray 
towards  it.  Assume  elevation  of  starting  point 
and  note  it.  Now  traverse  all  the  way  around 
the  area,  locating  as  you  go  the  position  and 
elevation  of  all  critical  points  along  the  trav- 
erse. Fill  in  all  horizontal  detail  along  and 
near  the  traverse,  inside  the  area,  within  easy 
estimating  distance  (a  couple  of  hundred 
yards)  by  estimation  and  farther  off  by  inter- 
section methods. 


SKETCHING  METHODS  83 

In  traversing  around  the  area,  in  addition  to 
cuts,  fills,  orchards,  etc.,  locate  the  following: 

1.  Every  stream  or  drainage  line  crossing 
the  traverse  or  running  close  to  it.     Note 
the  direction  of  its  flow  and  its  fall.     If 
this  is  not  at  once  apparent,  take  time  to 
find  out.     This  is  important. 

2.  Every  house  or  other  feature  easily  iden- 
tified near  the  traverse,  which  may  later 
be  useful  in  finding  yourself.     Sometimes 
some   feature   outside   of   the   area   may 
be  extremely  valuable.     For  example,  a 
tall    chimney    some    hundreds    of    yards 
from  the  area  may  be  visible  from  all 
points  in  it;  to  locate  this  by  intersection 
early  in  the  work  may  save  much  time 
later. 

3.  The  high  points  between  drainage  lines 
along  the  traverse   (determine  and  note 
their    elevations).      Proceeding    simulta- 
neously with  the  traversing,  dot  in   (ac- 
cording to  the  slope  of  the  ground)  and 
mark  the  crossing  points  of  the  contours 
between  critical  points  along  the  traverse 


84  SKETCHING  METHODS 

whose  elevations  have  been  determined. 
Do  not  draw  any  contours  yet ;  wait  until 
later  when  you  have  the  stream  line  and 
ridge  framework  completed  and  can  see 
the  area  as  a  whole.  The  big  features  will 
then  be  distinct,  and  the  little  ones  will 
take  care  of  themselves. 

ADJUSTMENT  TO  CLOSE. 

When  you  reach  a  point  from  which  the 
starting  point  can  be  seen,  you  will  probably 
find  that  the  ray  to  that  point  does  not  pass 
directly  through  it.  This  is  to  be  expected. 
If  the  error. is  less  than  10  per  cent  of  the 
entire  length  of  the  traverse,  it  is  satisfactory. 
If  it  is  greater,  there  has  probably  been  some 
error  in  your  orientation.  If  you  are  not  able 
to  determine  just  where  the  mistake  occurred, 
distribute  the  error  by  adjustment.  To  do  this, 
move  the  last  point  to  or  from  the  point  of 
starting,  the  next  traverse  line  a  little  less  in 
the  same  direction,  and  the  next  one  a  little 
less  than  the  previous  one.  Remember  the 
scale  you  are  using  and  the  scale  width  of  a 
road  as  it  is  drawn  on  the  sketch.  Do  not 


SKETCHING  METHODS  85 

waste  time  in  making  this  adjustment,  but  in 
making"  it,  be  sure  that  you  do  not  make  an 
angle  between  roads  which  is  noticeably  dif- 
ferent from  the  actual  ground  angle  made  by 
the  roads.  Otherwise  some  one  may  be  mis- 
led. Your  sketch  will  have  errors  in  it,  but  it 
must  not  contain  misleading  or  deceptive  in- 
formation. 

COMPLETING  SKETCH. 

Having  traversed  completely  around  your 
area  and  having  noted  the  location  of  all 
drainage  lines  crossing  its  borders,  you  will 
have  a  pretty  fair  idea  as  to  which  is  the  main 
stream  line  and  where  it  lies.  You  must  now 
find  out  how  the  smaller  stream  lines  connect 
up  with  it  in  the  area  in  order  to  complete 
your  framework.  It  is  now  time  to  traverse 
into  the  interior.  Select  a  road  or  trail  if  one 
is  nearby;  if  not,  select  some  point  in  the  in- 
terior and  draw  a  ray  to  it,  being  careful  with 
the  orientation  when  you  draw  it.  Traverse 
along  the  road  or  ray  and  keep  going  until  it 
seems  advisable  to  stop.  Then  plot  your  posi- 
tion, fill  in  flat  detail  up  to  your  location,  deter- 


86  SKETCHING  METHODS 

mine  your  elevation,  and  then,  after  orienting 
the  board,  draw  rays  to  such  stream  junctions 
and  high  points  as  seem  to  be  valuable.  In  this 
manner,  traverse  across  the  entire  area,  locating 
stream  lines,  stream  junctions,  ridges  and  hill- 
tops, fill  in  flat  detail,  determine  elevations  as 
you  go  and  note  those  of  critical  points  along 
and  ne^r  your  traverse.  It  may  be  necessary 
to  traverse  across  the  area  in  the  other  direc- 
tion before  all  critical  points  are  determined, 
but  on  such  a  small  area,  it  will  probably  not 
be.  After  having  'located  the  drainage  frame- 
work and  ridge  lines  and  determined  their 
elevations,  you  are  ready  to  contour.  This 
should  be  done  by  noting  the  slopes  as  uni- 
form, concave  or  convex  and  spacing  the  con- 
tour lines  accordingly.  After  a  little  practice, 
it  should  be  possible  to  contour  any  area  that 
the  sketcher  has  been  over,  from  one  or  two 
places  from  which  he  is  able  to  see  the  slopes. 
Until  the  sketcher  becomes  pretty  familiar 
with  ground  forms  and  their  representation  by 
contours,  he  should  take  time  to  dot  in  the 
crossing  points  of  the  contour  lines  between 
all  adjacent  critical  points.  This  will  take  a 


SKETCHING  METHODS  87 

little  longer,  but  will  save  much  time  later 
because  of  the  practice  it  gives  the  hand  and 
eye. 

Put  on  the  title  as  described  on  Page  43, 
and  the  sketch  is  finished. 

OUTPOST  SKETCH 

In  the  execution  of  an  outpost  sketch,  which 
is  made  on  a  scale  of  6  inches  to  the  mile, 
V.  I.  10  feet,  the  methods  followed  are  the 
same  as  those  of  a  position  sketch,  except  that 
the  sketcher  is  confined  to  one  side  of  the  area. 

Points  along  the  outpost  line  are  located  by 
traversing,  while  those  to  the  front  are  de- 
termined by  intersection  or,  in  some  cases,  by 
estimation,  as  for  instance,  where  a  feature 
can  be  seen  from  one  place  on  the  line  only. 

Having  made  two  or  three  position  sketches, 
the  beginner  should  be  able  to  start  at  one  end 
of  the  line  and  carry  his  operations  along  to 
the  other  end  and  then  from  some  advantageous 
position  contour  the  area. 

A  little  study  of  the  area  before  starting 
the  sketch  will  be  of  value  in  determining  the 
best  method  to  follow. 


88  SKETCHING  METHODS 

Traverse  the  outpost  line,  sketching  it  as 
you  go,  and  drawing  rays  from  different  sta- 
tions to  points  in  the  foreground,  thus  locating 
them  by  intersection. 

The  angle  between  the  intersection  lines 
should  be  as  near  90  degrees  as  possible.  There- 
fore, the  points  on  a  straight  line  from  which 
the  intersecting  lines  are  drawn,  should  be  far 
enough  apart,  if  the  ground  will  permit,  to 
secure  this.  It  is  thus  evident  that  the  farther 
out  the  points  are,  the  farther  apart  should  be 
the  points  from  which  the  intersecting  lines 
are  drawn.  Conversely,  the  nearer  the  ob- 
ject, the  shorter  need  be  the  distance  between 
the  points  on  the  traverse  line,  from  which  the 
rays  are  drawn. 

The  distance  to  be  sketched  to  the  front  de- 
pends upon  the  time  available  and  the  char- 
acter of  the  country.  In  all  practice  work,  the 
sketcher  should  include  the  area  as  far  to  the 
front  as  he  can  see. 

It  is  frequently  the  case  in  outpost  sketch- 
ing that  it  is  possible  to  locate  and  draw  in  one 
end  and  the  direction  line  of  a  straight  road, 
fence  line,  railroad  track,  or  telegraph  line. 


SKETCHING  METHODS  89 

If  this  can  be  done,  all  points  along  it  are 
accurately  located  by  drawing  a  ray  to  them 
from  determined  points  along  the  traverse, 
thereby  completing  the  intersection. 

In  contouring  the  outpost  sketch,  the  same 
methods  are  followed  as  in  the  position  sketch. 
Ttie  stream  line  and  ridge  frame  work  have 
been  secured  by  the  sketcher  in  his  traverse, 
and  it  only  remains  to  interpolate  the  contours 
according  to  the  slopes  of  the  ground  as  they 
appear  to  the  sketcher. 

Any  part  of  the  area  that  cannot  be  seen, 
as  the  far  side  of  a  ridge  parallel  to  the  trav- 
erse, is  drawn  in  by  broken  contour  lines, 
which  indicate  that,  in  the  opinion  of  the 
sketcher,  the  ground  is  shaped  as  shown  by 
them  although  he  has  not  visited  it. 

Field  glasses  may  be  of  use  in  outpost 
sketching  in  picking  out  objects  on  which  to 
intersect  or  for  discovering  folds  in  the  ground 
that  are  not  visible  to  the  naked  eye. 

PLACE  SKETCH 

A  place  sketch  is  one  in  which  the  sketcher 
is  limited  to  a  single  point  of  observation  over- 


90  SKETCHING  METHODS 

looking  the  area  to  be  sketched.  The  details 
to  be  shown  are  the  same  as  on  a  position  or 
outpost  sketch. 

If  made  to  extend  a  road  or  position  sketch 
farther  toward  the  enemy  than  can  be  reached 
by  the  sketcher,  the  place  sketch  will  be  at  the 
scale  of  the  sketch  thus  extended,  otherwise 
at  6  inches  to  the  mile  and  10- foot  V.  I. 

The  methods  of  work  described  for  making 
a  position  and  outpost  sketch  are  followed,  ex- 
cept that  the  location  of  points  is  determined 
by  estimation,  assisted  by  intersection  methods 
where  possible. 

It  is  advisable  to  select  some  few  prominent 
features  in  the  area,  determine  their  position 
and  elevation  as  carefully  as  possible,  and  then 
use  them  as  reference  points  in  locating  other 
points.  A  road,  a  hedge  fence,  a  wire  fence, 
a  railroad  or  any  such  feature  should  be  locat- 
ed and  drawn  in  as  soon  as  possible  and  used 
for  basing  other  estimates  and  for  locating 
points  along  it  by  intersection. 

Parts  of  the  area  that  cannot  be  seen  but 
which  the  sketcher  is  able  to  estimate,  should 


SKETCHING  METHODS  91 

be  represented  by  broken  lines,  as  in  outpost 
work. 

Place  sketching  is  extremely  valuable  to  the 
beginner  who  has  progressed  through  position 
and  outpost  sketching,  on  account  of  the  prac- 
tice that  it  gives  in  estimating  distances. 

ROAD  SKETCH 

Before  taking  up  road  sketching,  the  be- 
ginner should  be  able  to  make  a  position  sketch 
and  should  have  made  a  few  outpost  and  place 
sketches,  for  the  benefit  of  the  practice  in  in- 
tersection and  estimation  which  he  gains  by 
them.  He  should  also  learn  something  of  what 
can  be  shown  to  advantage  on  a  3-inch  scale. 

It  is  advisable  to  make  one  or  two  short 
road  sketches  dismounted  before  taking  up  the 
road  sketching  proper,  which  is  done  mounted. 

The  methods  followed  in  road  work  are  a 
combination  of  those  used  in  the  other  classes 
of  sketches  which  have  been  described.  The 
scale  is  usually  3  inches  to  1  mile  with  V.-  I. 
20  feet.  The  sketcher  lays  the  board  on  the 
ground  or  places  it  on  his  knees  as  he  sits  down. 


92  SKETCHING  METHODS 

The  road  sketch  should  include  all  the 
country  for  400  yards  to  each  side  of  the  road, 
all  artillery  positions  within  several  miles  and 
all  commanding  positions  within  rifle  range  of 
about  1  mile.  It  should  show  any  prominent 
landmarks  and  where  roads,  railroads,  etc., 
come  from  and  go  to,  the  names  of  rivers  and 
larger  streams,  of  the  families  living  at  cross 
roads  or  in  isolated  houses,  of  towns  or  vil- 
lages, as  well  as  all  information  that  is  given 
in  position,  outpost,  or  place  sketches. 

Arriving  at  his  second  station,  the  sketcher 
should  draw  in  not  only  all  horizontal  detail 
from  the  first  station  but  should  contour  the 
area  he  has  passed  over  before  starting  on  his 
next  traverse.  It  is  for  this  reason  that  it  is 
considered  better  for  the  beginner  not  to  at- 
tempt to  make  a  road  sketch  until  he  is  some- 
what practiced  in  sketching  methods. 

Do  not  waste  time  in  orienting,  but  after 
laying  board  down  or  standing  up  with  it 
leveled  in  front  of  and  pressed  against  the  body, 
orient  by  backsight,  and  check  by  noting  that 
arrow  on  board  is  to  north. 


SKETCHING  METHODS  93 

With  the  board  held  pressed  against  the 
body,  to  draw  a  ray  to  a  distant  object,  first 
orient  the  board,  then  pivot  the  ruler  around 
the  pin  to  its  approximate  position,  and  glanc- 
ing down  at  the  ruler  and  at  the  object  alter- 
nately, determine  when  the  ruler  is  pointing  at 
the  object.  Glance  at  the  orientation,  care- 
fully secure  the  ruler  with  finger  or  thumb, 
and  then  draw  the  ray.  This  will  be  found 
quite  difficult  to  do  at  first,  but  a  little  prac- 
tice will  make  it  easy.  Points  determined  by 
intersection  of  rays  taken  in  this  manner  are 
very  accurately  located  after  some  practice. 

The  road  sketch  is  carried  along  in  the  man- 
ner indicated  from  station  to  station,  being 
completed  at  each  point  before  moving  on  to 
the  next. 

Many  points  within  400  yards  of  the  road 
will  not  be  visible  to  the  sketcher  from  his 
position  opposite  them  in  the  road,  but  they 
may  be  from  some  point  further  on.  In  any 
case,  make  it  a  rule  not  to  leave  the  road.  Fill 
in  such  places  as  you  think  they  are,  as  de- 
scribed in  outpost  work,  or  leave  them  blank, 


94  SKETCHING  METHODS 

as  their  character  will  be  seen  by  the  reader 
of  the  sketch. 

In  case  the  sketch  should  threaten  to  run  off 
the  paper,  the  procedure  is  to  fill  in  the  detail 
a  little  beyond  your  station  (which  is  now 
close  to  the  edge  of  the  paper)  and  then, 
choosing  a  new  point  of  beginning  on  the 
paper,  locate  your  station  there,  draw  a  mag- 
netic-meridian line  nearby,  and  duplicate  the 
filling  in  previously  done,  around  and  be- 
yond it. 

Go  right  ahead  with  this  part  just  as  though 
the  other  part  was  a  different  sketch,  but  when 
the  sketch  is  finished,  cut  the  paper  between 
the  two  parts,  and  laying  the  points  which 
you  filled  in  twice  (once  near  the  edge  of  the 
paper  and  again  when  you  started  the  new 
part),  one  over  the  other,  turn  the  papers  'un- 
til the  M.  M.  lines  of  the  two  parts  are  par- 
allel, and  then  paste  them  together  in  that 
position.  The  sketch  may  run  off  the  paper 
several  times,  but  so  long  as  the  finished  sketch 
shows  the  meridian  lines  of  all  different  parts 
parallel  to  each  other,  this  is  immaterial. 


SKETCHING  METHODS  ^ 

In  mounted  work,  the  sketcher  must,  while 
controlling  the  horse  and  riding  along  the 
road,  jot  down  the  features  as  they  are  passed. 
This  is  done  on  the  pad  as  described  on 
Page  34. 

Practice  in  noting  down  features  wrhile 
riding  at  a  trot  should  be  had  before  going 
out  to  make  a  sketch.  It  is  quite  difficult  for 
some  to  learn,  but  anyone  can  do  it  with 
practice. 

System  in  methods  of  work  is  most  impor- 
tant, as  time  is  a  big  factor  in  mounted  work. 
All  sketching  is  done  as  in  road  sketching  dis- 
mounted. The  board  is  swung  under  the  left 
arm  by  the  cord  passing  over  the  shoulder,  and 
mthe  watch  (if  using  the  stop  watch)  and  pad 
are  held  in  the  left  hand,  finger  close  to  the 
stop  of  the  watch.  Using  the  stop  watch  and 
pad  is  largely  for  convenience.  Satisfactory 
mounted  work  may  be  done  by  using  an  ordi- 
nary wrist  watch  on  inner  side  of  left  wrist, 
from  which  the  time  of  passing  a  feature,  etc., 
may  be  noted  on  a  pad  held  in  left  hand. 

The  reins  are  held  in  the  right  hand,  over 
left  wrist,  or  with  a  knot  tied  in  them  across 


96  SKETCHING  METHODS 

the  pommel  of  the  saddle  where  they  can  be 
quickly  grasped. 

If  you  have  an  assistant,  which  is  desirable, 
have  him  carry  the  board  and  hold  your  horse 
when  you  halt.  The  assistant  should  be  with 
you  while  rating  the  horse  and  ride  either 
abreast  of  or  behind  you  as  he  is  to  do  during 
the  sketching. 

Immediately  after  mounting,  take  the  pad 
in  left  hand.  As  the  horse  starts,  press  the 
stop,  being  careful  to  see  that  stop  watch  is  at 
zero. 

Keep  your  eyes  on  the  country  and  on  your 
watch  alternately  so  that  when  you  see  a  fea- 
ture, you  will  not  have  to  hunt  for  the  proper 
place  on  the  pad  to  locate  it.  It  may  be  nec- 
essary at  first  to  stand  in  your  stirrups  and 
lean  forward  with  arms  close  in  while  making 
the  marks  in  order  to  get  readable  ones.  Note 
the  direction  erf  flow  of  the  stream  lines  as 
you  pass  them. 

At  first,  traverse  about  a  minute  at  a  time 
and  then  dismount  and  complete  the  sketch  in 
the  same  manner  as  in  road  sketching  dis- 
mounted. The  time  spent  in  traversing  is 


SKErCIIf\(;  METHODS  97 

small  in  comparison  with  that  spent  in  plot- 
ting the  notes  taken. 

Arriving  at  a  halting  place,  stop  the  horse, 
press  the  watch  stop  to  secure  correct  time  or 
note  same  from  watch,  throw  sketch-board 
cord  over  the  head  and  lay  the  board  on  the 
ground,  or  sit  down  and  place  it  on  your  knees. 
It  is  better  to  lie  down  on  the  ground  on  the 
stomach  and  with  pad  at  hand  and  the  board 
on  the  ground,  measure  off  the  minutes  of 
travel  and  fill  in  flat  detail  and  critical  points 
according  to  the  notes.  Then  orient  the  board 
and  draw  a  ray  to  the  new  station  or  in  the 
new  direction  along  the  traverse.  Then,  tak- 
ing the  board  up  as  previously  described,  con- 
tour the  sketch  up  to  your  position. 

In  field  service,  the  information  desired  in 
a  road  sketch  is  largely  that  which  will  en- 
able another  to  follow  the  reconnoitered  road. 
For  this  reason,  contouring  is  of  less  impor- 
tance than  direction,  distance,  land-marks, 
and  condition  and  practicability  of  roads.  In 
learning  how  to  sketch,  however,  it  is  consid- 
ered-necessary that  the  sketcher  practice  con- 
touring in  road  sketching,  not  so  much  because 


98  SKETCH  IXC  METHODS 

he  will  do  this  in  service  as  because  the  prac- 
tice in  rapid  contouring  is  invaluable  in  the 
study  of  ground  forms  and  their  representa- 
tion. 

RECONNAISSANCE  SKETCHES. 

The  tactical  situation  and  the  intentions  of 
the  commander  will  indicate  in  each  case  the 
information  that  is  especially  desired.  The 
information  secured  is  conveyed  by  means  of 
a  sketch  amplified  by  a  report  in  marginal  notes 
numbered  serially.  All  information  that  it  is  pos- 
sible to  show  clearly  is  contained  in  the  sketch. 
The  report  consists  of  descriptions  of  features 
and  objects,  measurements,  material,  construc- 
tion, etc.,  which  cannot  be  conveyed  in  a  sketch. 
The  serial  reference  numbers  should  run  in 
order  on  the  margin.  The  numbers  are  placed 
on  the  sketch  near  the  object  to  which  they 
pertain,  so  that  it  will  be  clear  to  what  they 
refer.  In  making  the  notes,  clearness  and 
brevity  are  desirable.  Such  terms  as  before, 
behind,  this  side  of,  etc.,  should  be  avoided  and 
compass  directions  used.  The  terms  left  and 
right  may  be  used  in  referring  to  the  banks  of 
a  stream  in  which  case  the  sketcher  is  assumed 
to  be  facing  down  stream. 


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